Your main choice will have to be either:
Intel & nVidia
AMD & ATI
I chose the latter purely for support, not as fast as Intel but still very good.

Most people don't know that AMD is having financial difficulties, nothing to do with the latest recession, though doesn't help, but because there CPU's don't perform as well as Intel!

But just imagine if the company folded! you would no longer have the competition & the price of computers would skyrocket & quality would drop, horid thought, would be like Windows, Microsoft have no competition, that's why the price is ridiculous!!

Getting a little off track here Mr Chris, but just had to say something!