Games I've been running under Windows 7 x64 Ultimate RC 1, with an EVGA GTX 285:
Far Cry 2, Fallout 3, Assassin's Creed, Oblivion, Prototype, Crysis, Crysis Warhead, Half Life 2, Half Life 2 Episodes 1 and 2, Portal,  STALKER: Clear Sky, STALKER: Shadow of Chernobyl, Rainbow Six Vegas, Call of Duty 4 and 5,  and Sims 3.
And the online versions of all the above, where applicable.
You might want to check your drivers for those devices and make sure you're using the manufacturer drivers and not the crap generic drivers Windows 7 installs. I've read of reports of Windows updates rolling drivers back, although I've never seen it happen before, and it's only been from one person here who I've seen claim that, so I'm kind of skeptical about that one. But it can't hurt.