If you aren't a fan of Ubuntu's new "Unity" interface, weblog OMG! Ubuntu! shows us how to get the old GNOME 2-style look back with just a few tweaks (and without having to downgrade).
Ubuntu may not have the choice to log into a GNOME Classic environment, but it turns out you can still install that feature from the Ubuntu Software centre. Then, with a few tweaks — like installing the old Ubuntu menu bar indicators, fixing problems with Compiz, and putting the Ubuntu logo back in the upper left-hand corner, you'll barely be able to tell the difference between your new desktop and the GNOME desktop of yore. If the more GNOME 2-like Mint isn't suiting you, and you don't want to switch to something altogether different like KDE, this could be a good way to get your classic Ubuntu interface back. Hit the link for the full instructions.
[How to] Make Ubuntu 11.10 Look and Feel Like GNOME 2 [OMG! Ubuntu!]