Gnome 2 + Compiz + Gnome-Do completely and utterly rocks, particularly with a dual monitor setup.
KDE was a bit of a mess last I checked. Some people are saying XFCE is maybe somewhat Gnome-2-ish?
I chose KDE but your requirements may vary. The cool part about linux is Live CDs/USB drives. It's not difficult to try out new things.
I've intentionally been sitting on the fence for over a year now. Once Fedora 14 goes EOL, going to have to make the move.
What I have now is a dream setup (gnome 2, gnome-do, compiz, emerald theme mamnager), so have been in no rush. Was hoping Gnome issues would get sorted out; i.e. they'd listen to the power users screaming bloody murder. Apparently not, or not entirely.
I'll take gnome 3 for a spin, it can't be thaaaat bad (I hope); if I'm appalled, check out XFCE, and then, if need be, KDE (KDE felt complex/clunky compared to Gnome 2 when I made the comparison a couple of years ago, maybe things have changed)