Only if you want to run things in DX10, which its not really worth it just for that.

Tried age of conan the other day running maxed out in dx9 and it ran at a solid 60fps, switched it onto dx10 mode ( which i believe is still in testing) and it looked worse than dx9 and only ran at 30fps.

Dx10 really hasnt taken off as I originally thought it might, but with games like CoD4 coming out, looking amazing, and running completely in dx9 why do they really need a dx10 at this point.

IMO its gonna be a long time before we see games natively supporting dx10 and not just having extra bits of dx10 bolted on.