I'm using XP and don't plan to switch to Vista for another 3 years. It's still not fully developed. I'm currently studying to become a programmer, and we're analyzing operating systems. The first version of XP was also bad, but after Service Pack 1 and 2 were released, it was fixed. The same will happen with Vista. At the academy, we only reviewed it in terms of services and processes, and there were already several glitches. I haven't used Vista, so I won't make any strong claims. But for now, I'll stick with XP. Now, regarding DirectX 10, for those who don't understand what it is, I'll say that it's a set of DLL files containing code to improve system performance. And if someone doesn't know, DirectX 10 is already available on XP! And as Night Nazgul said, I can prove it.