I’ve been using Ubuntu at home on one of my computers for close to a year now. I’ve been pretty happy with it, although Gnome struggled on my computer (a circa 2003 Athlon). Switching to Xfce fixed that, and my one remaining problem was Firefox.
I recently upgraded to Firefox 3 (see this video for how to do that), and it’s made a HUGE difference. The one issue I had was that I could get it to start – I hadn’t realized that the executable was now firefox-3.0 instead of firefox. Makes sense, though.