I ran Ubuntu for about a month but had to revert back to Windows. I loved everything about Ubuntu except for one thing: multi-monitor support. Out of box, two monitors one one video card worked great. But, when I ran three or four monitors on two video cards (both nvidia btw), the graphics were slow and 3d didn't work. If Ubuntu were to support 3d and be fast enough to do fast window rendering out-of-box, I'd move back to Ubuntu in a heartbeat.