I've tested Ubuntu 12.04 from live usb before executing the automagic update (from 11.10 to 12.04) and everything was fine. Then, after updating, I couldn't even get Unity 2D to work. I've installed Gnome packages, so I can use Gnome classic (only the "with no effects" option works).
Does any one know how to debug Ubuntu/Unity to try to get it working? (Or I'll need to do a fresh install...)