I was originally going to build something else but i started messing around with a core i7 build and its only a few hundred more so this is what i came up with not sure how compatible everything is but i have a case and an os already so just need some advice on the rest. also not sure weather to go with a single gpu or crossfire/sli this rig will be used mostly for gaming so let me know what you guys think. ASUS P6T EVGA GeForce GTX 260 Core 216 Superclocked Edition 896MB PC Power & Cooling S75QB 750W Intel Core i7 920 CORSAIR DOMINATOR 3GB 1600 Western Digital VelociRaptor 300GB Western Digital Caviar Black 1TB LG Black 6X Blu-ray
Better graphics card: http://www.newegg.com/Product/Product.aspx?Item=N82E16814150330 Apart from that it's a nice build, though don't forget the case! Just be advised PC Power & Cooling units aren't that quiet.
I wouldn't consider SLI, not like that anyway. If you want SLI, wait a couple of weeks until the GTX295 is released, or buy a Radeon HD4870X2.