Anything that will run on Vista will run on DX10.
DX10 is simply a name for the latest generation video card.
The question is whether the game will use the increased capabilities of the new technology. For the answer to that, go to the grocery store and pick up a copy of Maximum PC magazine. They specialize in games and the hardware needed to play them.
It's interesting that you would pay an extra $500 for the latest video card without investigating which games take advantage of it.
Well, (blush, blush) actually, you give me more credit then I'm entitled to. You see, it came with the system. I didn't even know what a DX is/was