Best gpu that'll work with my system?

[facce]

I'm doing a low cost upgrade of a 4-y.o. pc. Recently put in a new cpu (free) and psu. It's come time to choose a video card, and I admit I'm befuddled by the cornucopia of choices. Let's say I'd like to play Crysis and have it look good on a 1680 x 1050 monitor.

Current system:
Athlon x2 5600+ Brisbane 2.9Ghz @ 65 watts
Gigabyte M55sli-s4 mobo
Nvidia 7600gs gpu
2 x 1gb PNY DDR2 800 ram
320gb PATA HDD
DVD-RW
card reader
Corsair 400cx, 400 watts with 30A on +12V rail

Would the Nvidia GTS 250 work with this setup powerwise? And if so, is it overkill with the other components? (Budget is not the primary concern, but I'm not trying to waste money.) How about a green 9800gt? Or a Radeon 4770? 4670? Or what? Thanks.

[wazza300]

why not a 5770? they use less power than 4000 series ati's and alot less than anything nvidia has,i get 60-80+ even hitting 100fps inside buildings all on highest settings in crysis