Update 12/15/2011: Concerning bug report here:
https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/885939
This change would affect all users, as it's system-wide, and it would also be reverted by an upgrade of the package "gnome-session-fallback". But as I don't want to leave you with a session option you can't use anyway, I think it's better than creating a custom session. And those package shouldn't be upgraded too often anyway.
gksudo gedit /usr/share/gnome-session/sessions/gnome-classic.session
[GNOME Session]
Name=GNOME Classic
RequiredComponents=gnome-panel;gnome-settings-daemon;
RequiredProviders=windowmanager;notifications;
DefaultProvider-windowmanager=gnome-wm
DefaultProvider-notifications=notify-osd
IsRunnableHelper=/usr/lib/gnome-session/gnome-session-check-accelerated
FallbackSession=gnome-fallback
DesktopName=GNOME
Name=GNOME Classic
RequiredComponents=gnome-panel;gnome-settings-daemon;
RequiredProviders=windowmanager;notifications;
DefaultProvider-windowmanager=gnome-wm
DefaultProvider-notifications=notify-osd
IsRunnableHelper=/usr/lib/gnome-session/gnome-session-check-accelerated
FallbackSession=gnome-fallback
DesktopName=GNOME
That's all! After a relogin, the 'real' GNOME Classic should be running, with Mutter, btw.
If you get only your desktop wallpaper after login, thus missing the panels, and right-clicking on your desktop also doesn't work, also replace "gnome-wm" with "mutter" in its settings, like shown below. But if you want to run it with Compiz anyway, just move on to the next section.
[GNOME Session]
Name=GNOME Classic
RequiredComponents=gnome-panel;gnome-settings-daemon;
RequiredProviders=windowmanager;
DefaultProvider-windowmanager=mutter
DefaultProvider-notifications=notify-osd
IsRunnableHelper=/usr/lib/gnome-session/gnome-session-check-accelerated
FallbackSession=gnome-fallback
DesktopName=GNOME
Name=GNOME Classic
RequiredComponents=gnome-panel;gnome-settings-daemon;
RequiredProviders=windowmanager;
DefaultProvider-windowmanager=mutter
DefaultProvider-notifications=notify-osd
IsRunnableHelper=/usr/lib/gnome-session/gnome-session-check-accelerated
FallbackSession=gnome-fallback
DesktopName=GNOME
In addition, if you want to run "GNOME Classic" with Compiz instead, you just need to change another entry in its session settings. Or if you only want to affect your own or another specific user, there is another, similarly easy way.
These changes would affect all users, as they are system-wide, and they would also be reverted by an upgrade of the package "gnome-session-fallback".
gksudo gedit /usr/share/gnome-session/sessions/gnome-classic.session
[GNOME Session]
Name=GNOME Classic
RequiredComponents=gnome-panel;gnome-settings-daemon;
RequiredProviders=windowmanager;notifications;
DefaultProvider-windowmanager=compiz
DefaultProvider-notifications=notify-osd
IsRunnableHelper=/usr/lib/gnome-session/gnome-session-check-accelerated
FallbackSession=gnome-fallback
DesktopName=GNOME
Name=GNOME Classic
RequiredComponents=gnome-panel;gnome-settings-daemon;
RequiredProviders=windowmanager;notifications;
DefaultProvider-windowmanager=compiz
DefaultProvider-notifications=notify-osd
IsRunnableHelper=/usr/lib/gnome-session/gnome-session-check-accelerated
FallbackSession=gnome-fallback
DesktopName=GNOME
That's all! After a relogin, Compiz should be running.
This change would only your own or another specific user, and would not be reverted by an upgrade of the package "gnome-session-fallback".
copy /usr/share/applications/gnome-wm.desktop ~/.local/share/applications
gedit ~/.local/share/applications/gnome-wm.desktop
[Desktop Entry]
Type=Application
Name=Window Manager
Exec=compiz
NoDisplay=true
X-GNOME-Autostart-Phase=WindowManager
X-GNOME-Provides=windowmanager
X-GNOME-Autostart-Notify=true
X-Ubuntu-Gettext-Domain=gnome-session-3.0
Type=Application
Name=Window Manager
Exec=compiz
NoDisplay=true
X-GNOME-Autostart-Phase=WindowManager
X-GNOME-Provides=windowmanager
X-GNOME-Autostart-Notify=true
X-Ubuntu-Gettext-Domain=gnome-session-3.0
That's all! After a relogin, Compiz should be running.
Complementing these tips, here is a nice, simple guide to make the new Gnome Classic look and work even more like the old classic Gnome 2:
http://mandriver.users.sourceforge.net/classic-gnome-guide.html