This is a good place to start...
PCPartPicker part list:
http://pcpartpicker.com/p/XueC
Price breakdown by merchant: http://pcpartpicker.com/p/XueC/by_merchant/
Benchmarks: http://pcpartpicker.com/p/XueC/benchmarks/
CPU: Intel Core i5-3470 3.2GHz Quad-Core Processor ($149.99 @ Microcenter)
CPU Cooler: Corsair H60 74.4 CFM Liquid CPU Cooler ($59.99 @ Newegg)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($134.98 @ Outlet PC)
Storage: Western Digital Caviar Green 2TB 3.5" 5400RPM Internal Hard Drive ($89.70 @ Amazon)
Video Card: Asus GeForce GTX 660 Ti 2GB Video Card (2-Way SLI) ($249.70 @ Newegg)
Video Card: Asus GeForce GTX 660 Ti 2GB Video Card (2-Way SLI) ($249.70 @ Newegg)
Power Supply: SeaSonic 650W 80 PLUS Gold Certified ATX12V / EPS12V Power Supply ($93.49 @ Amazon)
Total: $1027.55
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-05-15 16:02 EDT-0400)
You still have about $500 left for case, SSD (optional), fans, card reader, optical drive, etc.