I run at 1650x1080 everythin maxxed and 2xAA and it runs fine - prob in the 30s but smooth as anything and thats with my pants graphics card
Presumably thats in DX9 mode. DX10 will be a different story methinks. My Q6600/8800GT/4GB runs at about 8fps with 2xAA, all ultra high, 1680x1050 and in DX10...unplayable basically.