>>5 Why not use Nvidia with AMD Processors? I know it can be done because I and many other people have done it before.
Also, ATI cards aren't horrible. In fact, the fastest ATI card is currently faster than the fastest Nvidia card according to New Egg. In other words, if you're looking at the lower end of the spectrum, go for Nvidia, but if you're looking for pure power regardless of price, chances are ATI is the way to go.
Anyways, take that with a grain of salt. Anything could happen between now and later. Actually, something might have already happened since I last looked at cards. So you should always do your own research when it comes to hardware. Trust me, it will save you a lot of money and frustration. And if you know your shit, you can impress women with it!