If you want to play HL2 on highest settings, don't go NVidia. The 6600GT will hit highest settings, but only at 60 fps. But you might as well get an X800 Pro and get 110 fps for roughly the same price.
nah ive got a 6600GT, everything maxed, full AA, full AF, and get like 40fps... i mean thats not perfect but u cant see any difference after 40fps neway.. too fast for ye eyes to even notice the difference
Yea 6600GT's are da bom!! but why the delux mobo? i got one cos the plain wasn't availiable but now you should be able to get one. Also id think about getting the 3200 cos it can oc real easy to 3500 speed (i got mine to 3800 with no vcore tweeks) if your not unlucky and the speed differance is minimal once you get to 3200 speeds any way is my experience. don't spend money on sli and then go ati as it won't work and last but not least make sure the grfx card you get is pci-e as the mobo doesn't have agp