Completely smooth for me at 1680*1050 on all max detail - unlike Metro 2033 which I can barely run in low detail:
Core I7 920 2.66GHz LGA1366
6GB * 1333MHz DDR3 (3*2GB)
NVidia GTX 295 (2*SLI)
NVidia 9800GTX (old card used for dedicated PhysX acceleration and secondary monitors)
Samsung 2233RZ 3D monitor + NVidia 3D Vision kit
Win 7 64 bit (Ultimate)
4*1TB 7200RPM disks (RAID 0 for system partition).
1,200W PSU, Thermaltake full-tower case (6 fan air-cooled)
It's no match for Knight Flyer's system, but it does the job (apart from Metro 2033), and cost me under $1,500 USD back in January - not counting the parts I scavenged from my old machine. I can also overclock it by up to 30% for a few hours at a time without heat issues.
I'm considering getting a couple of 480s to replace the 295, but it seems a lot to spend for a 50% speed increase. More video ram would be nice though, the 295 only has about 850MB per GPU.