The 64 bit drivers are the same between xp 64 and vista 64, at least for ati. I havn't had an nvidia card since I upgraded to vista 64, so I couldn;t tell you if they had different srivers for vista or xp.

I can say though that my ati cards here have been running great with opengl 2.0 for about 2-3 years. Only issue was a few bad driver releases about a year and a half ago, but rolling back to a previous release resolved those issues.

Way too many people take way too many things way too seriously.