Get a current generation video card with as much video ram as you can afford. I don't think the x2 cards have very mature drivers so get a single gpu card for your gaming machine.
Ya.

Right now I am recomending 9600 plus with 1G or more ram for reasons explained in other threads.

The ASUS EAH3870 X2 1GB TOP - which is quite a mouthful to say, by the way - packs in twin ATI RV680 GPUs, packaged together in Crossfire mode on a single PCI Express videocard.
Ya its a single card, but because its still using crossfire its just like two seperate cards.