Re: GTS 250 (512MB) vs GTS 250 (1GB) vs GTX 260 (896MB)
Get the first choice.
More VRAM (1GB, 896 MB etc.) is made for bigger monitors and higher resolution. Since you only run at 1366x768 you only need 512 MB.
Plus your CPU isn't the greatest, let's face it.
It won't bottleneck your first choice, but the others it will.
I don't think you will be able to max out Crysis or GTAIV.
Crysis is really demanding, and i7 rigs can BARELY max it out.
GTAIV is just crappily optimized and no one maxes it.
Other games, however, should be fine.
Amd Phenom ii 940 3.0 Stock cooler :( :( :(
XFX Geforce 260 Core 216
Antec 1200 with 600 watt Ocz Modxstream Pro
4 gigs DDR2 1066 RAM... 640 gig hard drive