If you want to max out i'd recommend either a 670 gtx or 7970 ghz edition.
Here my pick :
PCPartPicker part list:
http://pcpartpicker.com/p/oerf
Price breakdown by merchant: http://pcpartpicker.com/p/oerf/by_merchant/
Benchmarks: http://pcpartpicker.com/p/oerf/benchmarks/
CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($219.99 @ Amazon)
CPU Cooler: Zalman CNPS5X Performa CPU Cooler ($14.99 @ NCIX US)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($124.99 @ Newegg)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($39.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($49.99 @ Newegg)
Storage: Samsung 840 Series 120GB 2.5" Solid State Disk ($84.95 @ B&H)
Video Card: MSI GeForce GTX 670 2GB Video Card ($359.99 @ NCIX US)
Case: NZXT Source 210 Elite (Black) ATX Mid Tower Case ($49.98 @ Outlet PC)
Power Supply: XFX 650W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($65.48 @ NCIX US)
Optical Drive: Sony AD-7280S-0B DVD/CD Writer ($18.99 @ Newegg)
Monitor: Asus VS229H-P 21.5" Monitor ($149.99 @ Amazon)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($99.99 @ Newegg)
Total: $1264.32
(Prices include shipping, taxes, and discounts when available.)
Comes with a 670 gtx oc and if you need more power latter on you can still add another one 670 gtx cause the mobo and psu support it.