Slow down with buying such expensive stuffs!!
Here's one desktop from Nvidia I recommend since it's easy to assemble and packs a punch for your money. Though to get even better graphics, buy the same video card and put it in the computer and connect the cards with SLI, then buy the same ram cards.
The computer comes with a
GREAT looking case and an average processor, with one of the best fan systems I've ever seen.
It also includes the stuff you need to assemble the computer.
http://www.nvidia.com/object/product_geforce_pc_kit.html!!!!!!
It is proven that if you use the same graphics card and the same memory type (and brand) in the same computer it will be better than having two different graphics cards and ram cards.
Total price with this computer and the extra video card and memory $600-700!!!!
I recommend this package especially if you live in the US since it has cheaper shipping costs.