At this POINT I don't see why any gamer would switch his primary gaming OS from XP to Vista. Every benchmark test I've seen shows that XP is speedier than Vista. Why hamper your system with Vista? If you disable as many startup items and services as possible, XP's speed and responsiveness improves considerably. I also don't run a virus SCANNER since I know what I'm doing online, and I'd recommend that option to advanced users who know how to steer clear of the pitfalls that you can encounter online.

For Vista vs. XP references, see:

http://www.tomshardware.com/2007/01/29/xp-vs-vista/index.html

http://www.crn.com/software/198702242

http://blogs.zdnet.com/hardware/?p=797


That's a fair point . . . but, what about future games which will be Vista-only?
Arguably, Windows 98SE is a better choice for gaming than Windows XP, as it's faster on the same hardware and has much less overhead.
That doesn't mean that gamers shouldn't use XP though, the security reasons alone should tell you that.
Vista at the moment is not a great choice for most gamers, but when DirectX10 games become more common, it will become the platform of choice for enthusiasts wanting to play the latest games.When you mentioned DirectX 10 it reminded me of how Halo 2 will supposedly be available only for Vista. From what I've read, a company called Falling Leaf produces software that will allow ONE to play Halo 2 on Windows XP. Do you know anything about this? I also found these instructions that supposedly let one use Halo 2 on XP:

http://www.fallingleafsystems.com/forum/index.php?showtopic=81


Also found this INTERESTING article dealing with DX9/10 in XP and Vista:

http://arstechnica.com/journals/microsoft.ars/2007/2/14/7060

And more evidence:

http://news.zdnet.com/2100-9590_22-6220201.html


Also, Windows XP SP3 will be 10% faster than SP2:

http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9048658


Not looking too good for Vista at the moment.