What ATI graphics cards can i play crysis wih on good settings.?

the 3870 card is the best one they do at the moment. with a decent cpu and 2gb ram you will be able play it on high settings at full resolution. dont recommend very high though. as for a psu, 500w min really. sounds like you're upgrading. if so i would defiantly say get an 8800 series card for crysis tho.