The newest Card from Nvidia is the GTX 295, top of the range Dual core again will suit it well like a E8400. And of course a good Quad core.
http://www.nvidia.com/object/product...tx_295_us.html
With a price tag of upto $600 USD its an expensive card. However to run the thing properly you need a very high quality PSU of about 800W - 950W with a 12v@ 60a, which can set you back another $300-$500.
Im about to purchase a SilverStone 1500W with 12v@ 120a so i can run my system in SLI.