Get Vista if you want to see eyecandy in your games...that is if your system can handle it.

Yes, it's capable of running that video card.

I would get either of these ones instead, as they all are around the same price range, and they all have native 6-pin PCI-E connectors:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817159066

or

http://www.newegg.com/Product/Product.aspx?Item=N82E16817171018

or

http://www.newegg.com/Product/Product.aspx?Item=N82E16817701007

or

http://www.newegg.com/Product/Product.aspx?Item=N82E16817182044

Get this card:

http://www.soundblaster.com/products/product.asp?category=1&subcategory=208&product=16559

It's the best one out on the market, and it will suit all of your needs.