Install GNOME 3 on Ubuntu Natty (10.04)

Add the GNOME3 Personal Package Archive (PPA)

With Natty, Ubuntu comes with Unity installed as its default desktop environment. GNOME remains in Ubuntu’s universe package repository. However, it contains version 2.30 and not the newly released version 3:

user@ubuntu:~$ apt-cache show gnome
Package: gnome
Priority: optional
Section: universe/gnome
Installed-Size: 60
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Debian GNOME Maintainers <pkg-gnome-maintainers@lists.alioth.debian.org>
Architecture: amd64
Source: meta-gnome2
Version: 1:2.30+7ubuntu3
Depends: gnome-desktop-environment (= 1:2.30+7ubuntu3), gdm, gnome-themes-extras, gnome-games (>= 1:2.30), libpam-gnome-keyring (>= 2.30), gstreamer0.10-plugins-ugly (>= 0.10.14), gstreamer0.10-ffmpeg (>= 0.10.10), rhythmbox-plugins (>= 0.12.8) | banshee (>= 1.6), rhythmbox-plugin-cdrecorder (>= 0.12.8) | banshee (>= 1.6), synaptic (>= 0.63), system-config-printer-gnome (>= 1.0.0), totem-mozilla, epiphany-extensions, gedit-plugins, evolution-plugins (>= 2.30), evolution-exchange (>= 2.30) | evolution-mapi (>= 0.30), evolution-webcal (>= 2.28), software-center, gnome-codec-install, transmission-gtk, avahi-daemon, tomboy (>= 1.2) | gnote
Recommends: gnome-games-extra-data (>= 2.30), network-manager-gnome (>= 0.8), gnome-office (= 1:2.30+7ubuntu3), update-notifier, shotwell, liferea | evolution-rss | blam, menu-xdg, gdebi, mozilla-plugin-gnash
Suggests: gnome-dbg, openoffice.org-gnome, openoffice.org-evolution
Conflicts: gnome-cups-manager
Filename: pool/universe/m/meta-gnome2/gnome_2.30+7ubuntu3_amd64.deb
Size: 2126
MD5sum: fa2a01a8c704eb05374ed95c74f6e84a
SHA1: cb2bcd2a12ea289afbc923c49359ba1f6a295516
SHA256: f792b1d4c4887d27d8c9e3a3f6bd9c773e12fea459b86e07f876d78262cc827c
Description: The GNOME Desktop Environment, with extra components
 This is the GNOME Desktop environment, an intuitive and attractive
 desktop, with extra components.
 .
 This package depends on the standard distribution of the GNOME desktop
 environment, plus a complete range of plugins and other applications
 integrating with GNOME and Debian, providing the best possible
 environment to date.
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Origin: Ubuntu

This PPA contains packages from GNOME3 and their dependencies so they can be used in Ubuntu 11.04 (Natty).

user@ubuntu:~$ sudo add-apt-repository ppa:gnome3-team/gnome3
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver hkp://keyserver.ubuntu.com:80/ --recv 9D542E3D52C801D9F8E31682F1773AF13B1510FD
gpg: requesting key 3B1510FD from hkp server keyserver.ubuntu.com
gpg: key 3B1510FD: public key "Launchpad PPA for GNOME3 Team" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
user@ubuntu:~$ sudo apt-get update
root@ubuntu:~# sudo apt-get upgrade
root@ubuntu:/etc/apt/sources.list.d# aptitude upgrade
Resolving dependencies...
The following NEW packages will be installed:
  accountsservice{a} dconf-gsettings-backend{a}
  gir1.2-gnomebluetooth-1.0{a} gir1.2-gtk-3.0{a} gir1.2-peas-1.0{a}
  gir1.2-totem-1.0{a} gir1.2-totem-plparser-1.0{a} gnome-desktop3-data{a}
  gtk3-engines{a} gtk3-engines-unico{a} libaccountsservice0{a}
  libappindicator3-1{a} libaudit0{a} libavahi-ui-gtk3-0{a}
  libcamel-1.2-23{a} libcanberra-gtk3-0{a} libcanberra-gtk3-module{a}
  libcap2-bin{a} libdbusmenu-gtk3-3{a} libebackend-1.2-1{a}
  libedata-book-1.2-9{a} libedata-cal-1.2-11{a} libedataserverui-3.0-0{a}
  libgail-3-0{a} libgck0{a} libgcr-3-0{a} libgnome-control-center1{a}
  libgnome-desktop-3-0{a} libgnome-media-profiles-3.0-0{a} libgnomekbd7{a}
  libgtk-3-0{a} libgtk-3-bin{a} libgtk-3-common{a} libgtk-vnc-2.0-0{a}
  libgtkhtml-4.0-0{a} libgtkhtml-4.0-common{a} libgtkhtml-editor-4.0-0{a}
  libgtkmm-3.0-1{a} libgtksourceview-3.0-0{a}
  libgtksourceview-3.0-common{a} libgucharmap-2-90-7{a} libgvnc-1.0-0{a}
  libgweather-3-0{a} libindicator3-3{a} liblaunchpad-integration-3.0-1{a}
  libpeas-1.0-0{a} libpeas-common{a} libtotem0{a} libunique-3.0-0{a}
  libvte-2.90-9{a} libwebkitgtk-3.0-0{a} libwebkitgtk-3.0-common{a}
  libwnck-3-0{a} libwnck-3-common{a} sound-theme-freedesktop{a}
  zenity-common{a}
The following packages will be upgraded:
  aisleriot avahi-autoipd avahi-daemon avahi-utils baobab empathy
  empathy-common eog evolution evolution-common evolution-data-server
  evolution-data-server-common evolution-exchange evolution-plugins
  file-roller gcalctool gconf-defaults-service gconf-editor gconf2
  gconf2-common gdm gedit gedit-common gir1.2-freedesktop gir1.2-gconf-2.0
  gir1.2-glib-2.0 gir1.2-notify-0.7 gir1.2-soup-2.4
  gnome-accessibility-themes gnome-bluetooth gnome-disk-utility
  gnome-doc-utils gnome-games-common gnome-icon-theme gnome-keyring
  gnome-mahjongg gnome-media gnome-menus gnome-nettool gnome-orca
  gnome-power-manager gnome-screensaver gnome-screenshot gnome-search-tool
  gnome-session gnome-session-bin gnome-session-canberra
  gnome-session-common gnome-settings-daemon gnome-system-log
  gnome-system-monitor gnome-terminal gnome-terminal-data
  gnome-themes-selected gnome-user-share gnome-utils-common gnomine
  gsettings-desktop-schemas gucharmap ibus ibus-gtk libavahi-client3
  libavahi-common-data libavahi-common3 libavahi-core7 libavahi-glib1
  libavahi-gobject0 libavahi-ui0 libcanberra-gtk-module libcanberra-gtk0
  libcanberra-pulse libcanberra0 libdconf0 libebook1.2-10 libecal1.2-8
  libedataserver1.2-14 libegroupwise1.2-13 libevolution libgconf2-4 libgcr0
  libgdata-common libgdata11 libgdu-gtk0 libgdu0 libgirepository-1.0-1
  libgnome-bluetooth8 libgnome-keyring0 libgnome-menu2 libgnomekbd-common
  libgtk-vnc-1.0-0 libgucharmap7 libgweather-common libibus2
  libmetacity-private0 libmission-control-plugins0 libnautilus-extension1
  libnotify4 libpam-gnome-keyring libpolkit-agent-1-0 libpolkit-backend-1-0
  libpolkit-gobject-1-0 libpolkit-gtk-1-0 libquvi0 librsvg2-2
  librsvg2-common libsoup-gnome2.4-1 libsoup2.4-1 libstartup-notification0
  libtelepathy-glib0 libtelepathy-logger2 libtotem-plparser17
  libwebkitgtk-1.0-0 libwebkitgtk-1.0-common libwnck-common libwnck22
  libxklavier16 light-themes metacity metacity-common mousetweaks nautilus
  nautilus-data nautilus-sendto nautilus-sendto-empathy
  network-manager-gnome policykit-1 policykit-1-gnome python-gmenu
  python-ibus telepathy-butterfly telepathy-gabble telepathy-idle
  telepathy-logger telepathy-mission-control-5 telepathy-salut totem
  totem-common totem-mozilla totem-plugins ubuntu-artwork vinagre vino yelp
  yelp-xsl zenity
The following packages are RECOMMENDED but will NOT be installed:
  gir1.2-gtksource-3.0 gnome-icon-theme-symbolic
145 packages upgraded, 56 newly installed, 0 to remove and 7 not upgraded.
Need to get 175 MB/189 MB of archives. After unpacking 389 MB will be used.
Do you want to continue? [Y/n/?] y
root@ubuntu:~# sudo apt-get install gnome-shell
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  gir1.2-clutter-1.0 gir1.2-gkbd-3.0 gir1.2-json-glib-1.0 gir1.2-mutter-3.0
  gir1.2-polkit-1.0 gir1.2-telepathyglib-0.12 gir1.2-telepathylogger-0.2
  gir1.2-upowerglib-1.0 gjs gnome-icon-theme-symbolic libclutter-1.0-0
  libclutter-1.0-common libgjs0b libmozjs185-1.0 libmutter0 mesa-utils
  mutter-common
The following NEW packages will be installed:
  gir1.2-clutter-1.0 gir1.2-gkbd-3.0 gir1.2-json-glib-1.0 gir1.2-mutter-3.0
  gir1.2-polkit-1.0 gir1.2-telepathyglib-0.12 gir1.2-telepathylogger-0.2
  gir1.2-upowerglib-1.0 gjs gnome-icon-theme-symbolic gnome-shell
  libclutter-1.0-0 libclutter-1.0-common libgjs0b libmozjs185-1.0 libmutter0
  mesa-utils mutter-common
0 upgraded, 18 newly installed, 0 to remove and 7 not upgraded.
Need to get 6,630 kB of archives.
After this operation, 22.7 MB of additional disk space will be used.
Do you want to continue [Y/n]? y

Reboot. Choose GNOME for your desktop session at the login prompt.

Uninstall

root@ubuntu:~# sudo apt-get install ppa-purge
root@ubuntu:~# sudo ppa-purge ppa:gnome3-team/gnome3
...
The following packages will be DOWNGRADED:
  aisleriot avahi-autoipd avahi-daemon avahi-utils baobab empathy
  empathy-common eog evince evince-common evolution evolution-common
  evolution-data-server evolution-data-server-common evolution-exchange
  evolution-plugins file-roller gcalctool gconf-defaults-service
  gconf-editor gconf2 gconf2-common gdm gedit gedit-common
  gir1.2-clutter-1.0 gir1.2-freedesktop gir1.2-gconf-2.0 gir1.2-glib-2.0
  gir1.2-gtk-3.0 gir1.2-notify-0.7 gir1.2-soup-2.4
  gnome-accessibility-themes gnome-bluetooth gnome-disk-utility
  gnome-doc-utils gnome-games-common gnome-icon-theme gnome-keyring
  gnome-mahjongg gnome-media gnome-menus gnome-nettool gnome-orca
  gnome-power-manager gnome-screensaver gnome-screenshot gnome-search-tool
  gnome-session gnome-session-bin gnome-session-canberra
  gnome-session-common gnome-settings-daemon gnome-system-log
  gnome-system-monitor gnome-terminal gnome-terminal-data
  gnome-themes-selected gnome-user-share gnome-utils-common gnomine
  gsettings-desktop-schemas gucharmap ibus ibus-gtk libavahi-client3
  libavahi-common-data libavahi-common3 libavahi-core7 libavahi-glib1
  libavahi-gobject0 libavahi-ui0 libcanberra-gtk-module libcanberra-gtk0
  libcanberra-pulse libcanberra0 libclutter-1.0-0 libclutter-1.0-common
  libdconf0 libebook1.2-10 libecal1.2-8 libedataserver1.2-14
  libegroupwise1.2-13 libevolution libgconf2-4 libgcr0 libgdata-common
  libgdata11 libgdu-gtk0 libgdu0 libgirepository-1.0-1 libgjs0b
  libgnome-bluetooth8 libgnome-keyring0 libgnome-menu2 libgnomekbd-common
  libgtk-3-0 libgtk-3-bin libgtk-3-common libgtk-vnc-1.0-0 libgucharmap7
  libgweather-common libibus2 libmetacity-private0
  libmission-control-plugins0 libnautilus-extension1 libnotify4
  libpam-gnome-keyring libpeas-1.0-0 libpeas-common libpolkit-agent-1-0
  libpolkit-backend-1-0 libpolkit-gobject-1-0 libpolkit-gtk-1-0 libquvi0
  librsvg2-2 librsvg2-common libsoup-gnome2.4-1 libsoup2.4-1
  libstartup-notification0 libtelepathy-glib0 libtelepathy-logger2
  libtotem-plparser17 libwebkitgtk-1.0-0 libwebkitgtk-1.0-common
  libwnck-common libwnck22 libxklavier16 light-themes metacity
  metacity-common mousetweaks nautilus nautilus-data nautilus-sendto
  nautilus-sendto-empathy network-manager-gnome policykit-1
  policykit-1-gnome python-gmenu python-ibus telepathy-butterfly
  telepathy-gabble telepathy-idle telepathy-logger
  telepathy-mission-control-5 telepathy-salut totem totem-common
  totem-mozilla totem-plugins ubuntu-artwork vinagre vino yelp yelp-xsl
  zenity
The following NEW packages will be installed:
  gir1.2-gstreamer-0.10{a} gnome-js-common{a} libevdocument3{a}
  libevview3{a} libseed0{a} xulrunner-2.0-mozjs{a}
The following packages will be REMOVED:
  accountsservice{u} dconf-gsettings-backend{u} gir1.2-gkbd-3.0{a}
  gir1.2-gnomebluetooth-1.0{u} gir1.2-mutter-3.0{u} gir1.2-peas-1.0{u}
  gir1.2-polkit-1.0{u} gir1.2-telepathyglib-0.12{u}
  gir1.2-telepathylogger-0.2{u} gir1.2-totem-1.0{u}
  gir1.2-totem-plparser-1.0{u} gir1.2-upowerglib-1.0{u} gjs{u}
  gnome-desktop3-data{u} gnome-icon-theme-symbolic{a} gnome-shell{a}
  gtk3-engines{u} gtk3-engines-unico{u} libappindicator3-1{u} libaudit0{u}
  libavahi-ui-gtk3-0{u} libcamel-1.2-23{a} libcanberra-gtk3-0{u}
  libcanberra-gtk3-module{u} libcap2-bin{u} libdbusmenu-gtk3-3{u}
  libebackend-1.2-1{a} libedata-book-1.2-9{a} libedata-cal-1.2-11{a}
  libedataserverui-3.0-0{a} libevince3-3{a} libgail-3-0{u} libgck0{u}
  libgcr-3-0{u} libgnome-control-center1{u} libgnome-desktop-3-0{u}
  libgnome-media-profiles-3.0-0{u} libgnomekbd7{a} libgtk-vnc-2.0-0{u}
  libgtkhtml-4.0-0{u} libgtkhtml-4.0-common{u} libgtkhtml-editor-4.0-0{u}
  libgtkmm-3.0-1{u} libgtksourceview-3.0-0{u}
  libgtksourceview-3.0-common{u} libgucharmap-2-90-7{u} libgvnc-1.0-0{u}
  libgweather-3-0{u} libindicator3-3{u} liblaunchpad-integration-3.0-1{u}
  libmozjs185-1.0{u} libmutter0{u} libtotem0{a} libunique-3.0-0{u}
  libvte-2.90-9{u} libwebkitgtk-3.0-0{u} libwebkitgtk-3.0-common{u}
  libwnck-3-0{u} libwnck-3-common{u} mesa-utils{u} mutter-common{u}
  sound-theme-freedesktop{u} zenity-common{a}
0 packages upgraded, 6 newly installed, 157 downgraded, 63 to remove and 0 not upgraded.
Need to get 53.8 MB/58.7 MB of archives. After unpacking 406 MB will be freed.
Do you want to continue? [Y/n/?] y
Fetched 53.8 MB in 55s (973 kB/s)
Extracting templates from packages: 100%
Preconfiguring packages ...
dpkg: warning: downgrading libcanberra-pulse from 0.28-0ubuntu5~natty1 to 0.28-0ubuntu3.
(Reading database ... 141452 files and directories currently installed.)
Preparing to replace libcanberra-pulse 0.28-0ubuntu5~natty1 (using .../libcanberra-pulse_0.28-0ubuntu3_amd64.deb) ...
Unpacking replacement libcanberra-pulse ...
dpkg: warning: downgrading libcanberra0 from 0.28-0ubuntu5~natty1 to 0.28-0ubuntu3.
Preparing to replace libcanberra0 0.28-0ubuntu5~natty1 (using .../libcanberra0_0.28-0ubuntu3_amd64.deb) ...
Unpacking replacement libcanberra0 ...
dpkg: warning: downgrading libcanberra-gtk0 from 0.28-0ubuntu5~natty1 to 0.28-0ubuntu3.
Preparing to replace libcanberra-gtk0 0.28-0ubuntu5~natty1 (using .../libcanberra-gtk0_0.28-0ubuntu3_amd64.deb) ...
Unpacking replacement libcanberra-gtk0 ...
dpkg: warning: downgrading gconf2-common from 2.32.4-1ubuntu1~natty1 to 2.32.2-0ubuntu2.
Preparing to replace gconf2-common 2.32.4-1ubuntu1~natty1 (using .../gconf2-common_2.32.2-0ubuntu2_all.deb) ...
Unpacking replacement gconf2-common ...
dpkg: warning: downgrading libgconf2-4 from 2.32.4-1ubuntu1~natty1 to 2.32.2-0ubuntu2.
Preparing to replace libgconf2-4 2.32.4-1ubuntu1~natty1 (using .../libgconf2-4_2.32.2-0ubuntu2_amd64.deb) ...
Unpacking replacement libgconf2-4 ...
dpkg: warning: downgrading libpolkit-gobject-1-0 from 0.101-4~natty1 to 0.101-1ubuntu1.
Preparing to replace libpolkit-gobject-1-0 0.101-4~natty1 (using .../libpolkit-gobject-1-0_0.101-1ubuntu1_amd64.deb) ...
Unpacking replacement libpolkit-gobject-1-0 ...
dpkg: warning: downgrading libgcr0 from 3.0.3-2~natty1 to 2.92.92.is.2.32.1-0ubuntu2.
Preparing to replace libgcr0 3.0.3-2~natty1 (using .../libgcr0_2.92.92.is.2.32.1-0ubuntu2_amd64.deb) ...
Unpacking replacement libgcr0 ...
dpkg: warning: downgrading libgnome-keyring0 from 3.0.3-1~natty1 to 2.32.0-1ubuntu2.
Preparing to replace libgnome-keyring0 3.0.3-1~natty1 (using .../libgnome-keyring0_2.32.0-1ubuntu2_amd64.deb) ...
Unpacking replacement libgnome-keyring0 ...
dpkg: warning: downgrading gnome-keyring from 3.0.3-2~natty1 to 2.92.92.is.2.32.1-0ubuntu2.
Preparing to replace gnome-keyring 3.0.3-2~natty1 (using .../gnome-keyring_2.92.92.is.2.32.1-0ubuntu2_amd64.deb) ...
Unpacking replacement gnome-keyring ...
dpkg: warning: downgrading gconf2 from 2.32.4-1ubuntu1~natty1 to 2.32.2-0ubuntu2.
Preparing to replace gconf2 2.32.4-1ubuntu1~natty1 (using .../gconf2_2.32.2-0ubuntu2_amd64.deb) ...
Unpacking replacement gconf2 ...
dpkg: warning: downgrading file-roller from 3.0.2-0ubuntu1~natty1 to 2.32.1-0ubuntu4.
Preparing to replace file-roller 3.0.2-0ubuntu1~natty1 (using .../file-roller_2.32.1-0ubuntu4_amd64.deb) ...
Unpacking replacement file-roller ...
dpkg: warning: downgrading evince from 3.0.2-0ubuntu4~natty1 to 2.32.0-0ubuntu12.
Preparing to replace evince 3.0.2-0ubuntu4~natty1 (using .../evince_2.32.0-0ubuntu12_amd64.deb) ...
Unpacking replacement evince ...
dpkg: error processing /var/cache/apt/archives/evince_2.32.0-0ubuntu12_amd64.deb (--unpack):
 trying to overwrite '/usr/share/glib-2.0/schemas/org.gnome.Evince.gschema.xml', which is also in package evince-common 3.0.2-0ubuntu4~natty1
No apport report written because MaxReports is reached already
                                                              dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
dpkg: warning: downgrading totem-plugins from 3.0.1-0ubuntu2~natty1 to 2.32.0-0ubuntu10.
Preparing to replace totem-plugins 3.0.1-0ubuntu2~natty1 (using .../totem-plugins_2.32.0-0ubuntu10_amd64.deb) ...
Unpacking replacement totem-plugins ...
dpkg: warning: downgrading totem-mozilla from 3.0.1-0ubuntu2~natty1 to 2.32.0-0ubuntu10.
Preparing to replace totem-mozilla 3.0.1-0ubuntu2~natty1 (using .../totem-mozilla_2.32.0-0ubuntu10_amd64.deb) ...
Unpacking replacement totem-mozilla ...
Processing triggers for man-db ...
Processing triggers for libglib2.0-0 ...
Processing triggers for python-gmenu ...
Rebuilding /usr/share/applications/desktop.en_US.utf8.cache...
Processing triggers for bamfdaemon ...
Rebuilding /usr/share/applications/bamf.index...
Processing triggers for desktop-file-utils ...
Processing triggers for hicolor-icon-theme ...
Processing triggers for python-support ...
Errors were encountered while processing:
 /var/cache/apt/archives/evince_2.32.0-0ubuntu12_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install.  Trying to recover:
Setting up libpolkit-gobject-1-0 (0.101-1ubuntu1) ...
Setting up libgcr0 (2.92.92.is.2.32.1-0ubuntu2) ...
Setting up gconf2-common (2.32.2-0ubuntu2) ...
Setting up gnome-keyring (2.92.92.is.2.32.1-0ubuntu2) ...
Installing new version of config file /etc/xdg/autostart/gnome-keyring-pkcs11.desktop ...
Installing new version of config file /etc/xdg/autostart/gnome-keyring-secrets.desktop ...
Installing new version of config file /etc/xdg/autostart/gnome-keyring-ssh.desktop ...
dpkg: dependency problems prevent configuration of totem-mozilla:
 totem-mozilla depends on totem (= 2.32.0-0ubuntu10); however:
  Version of totem on system is 3.0.1-0ubuntu2~natty1.
dpkg: error processing totem-mozilla (--configure):
 dependency problems - leaving unconfigured
Setting up libcanberra0 (0.28-0ubuntu3) ...
Setting up libcanberra-gtk0 (0.28-0ubuntu3) ...
dpkg: dependency problems prevent configuration of totem-plugins:
 totem-plugins depends on totem (= 2.32.0-0ubuntu10); however:
  Version of totem on system is 3.0.1-0ubuntu2~natty1.
dpkg: error processing totem-plugins (--configure):
 dependency problems - leaving unconfigured
Setting up libgnome-keyring0 (2.32.0-1ubuntu2) ...
Setting up libgconf2-4 (2.32.2-0ubuntu2) ...
Setting up libcanberra-pulse (0.28-0ubuntu3) ...
Setting up gconf2 (2.32.2-0ubuntu2) ...
Setting up file-roller (2.32.1-0ubuntu4) ...
Processing triggers for libc-bin ...
ldconfig deferred processing now taking place
Errors were encountered while processing:
 totem-mozilla
 totem-plugins
Current status: 2 broken [+2].
Warning:  Something went wrong, packages may not have been reverted

Fix totem by uninstalling the ppa:gnome3-team/gnome3 packages and installing the packages from the standard Ubuntu Natty repository:

root@ubuntu:~# aptitude purge totem-common totem totem-mozilla totem-plugins
root@ubuntu:~# aptitude install totem totem-common totem-mozilla totem-plugins
The following NEW packages will be installed:
  totem totem-common totem-mozilla totem-plugins
0 packages upgraded, 4 newly installed, 0 to remove and 1 not upgraded.

Remove GNOME 3 gnome-shell:

root@ubuntu:~# aptitude remove gnome-shell
The following packages will be REMOVED:
  gnome-shell
0 packages upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
Need to get 0 B of archives. After unpacking 4,084 kB will be freed.
(Reading database ... 140981 files and directories currently installed.)
Removing gnome-shell ...
Processing triggers for libglib2.0-0 ...
Processing triggers for python-gmenu ...
Rebuilding /usr/share/applications/desktop.en_US.utf8.cache...
Processing triggers for bamfdaemon ...
Rebuilding /usr/share/applications/bamf.index...
Processing triggers for desktop-file-utils ...
Processing triggers for gconf2 ...
Processing triggers for man-db ...
Processing triggers for python-support ...
Current status: 32013 new [-1].

Once you reboot, you should be able to choose Ubuntu (Unity) for your desktop session.

References