You can always build around that card. Though Nvidia is dropping new driver support soon I believe.
You can also buy retail PCs that have graphics cards in them. Most reliable way to get them at the moment. So if you are after a complete system, that is the way to go.
OEM PCs like HP (top ranked so far), Dell (Avoid), Lenovo (average)
Mainstream builders like CyberPowerPC, NZXT's Build service, Newegg's ENIAC (Or just their pre-assembled PCs on their site, that aren't refurbs)
Or true Boutique builders like Digital Storm, Origin, Falcon Northwest...
Set a budget and lots of people here can post suggestions.