I am using an AM2+ system. My mobo is K10N780SLIX3 running a Phenom II 940 and I use a GTX260-216. I've had no issues with this combination, the card runs beautifully in the system and gives terrific performance in both native games and under wine (depending on how far wine itself has come along for a given title). I can't comment on the ATI card since I haven't used ATI since my switch to Linux years ago, but I've been really happy with my GTX260-216, that card is a beast.
No announcement yet.
Any update: HD Radeon 4xxx v.s. Nviida 260?