If dx10 is ever made available for Windows XP, that will spell the end for Vista. As it stands right now very few want that bloatware in the first place. Most PC users have had the feeling that Vista was forced on us by Microsoft just to increase it's revenue and bring in some cash. It's no different than Sony forcing it's Blu-Ray player on PS3 owners.
So take that Microsoft if dx10 makes it to XP.