PCPartPicker part list:
http://pcpartpicker.com/p/2SohY
Price breakdown by merchant: http://pcpartpicker.com/p/2SohY/by_merchant/
Benchmarks: http://pcpartpicker.com/p/2SohY/benchmarks/
CPU: AMD FX-8120 3.1GHz 8-Core Processor ($139.99 @ SuperBiiz)
CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler ($108.25 @ Amazon)
Motherboard: Gigabyte GA-990FXA-UD3 ATX AM3+ Motherboard ($119.99 @ NCIX US)
Memory: Patriot Signature 8GB (2 x 4GB) DDR3-1600 Memory ($72.99 @ Newegg)
Storage: Crucial M500 240GB 2.5" Solid State Disk ($129.29 @ Amazon)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($59.98 @ OutletPC)
Video Card: XFX Radeon HD 7970 GHz Edition 3GB Video Card ($403.30 @ Amazon)
Case: Cooler Master HAF 912 ATX Mid Tower Case ($59.99 @ Newegg)
Power Supply: Cooler Master i700 700W 80+ Bronze Certified ATX Power Supply ($49.99 @ Newegg)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.99 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($84.98 @ OutletPC)
Total: $1245.74
Built this AMD build as I like AMD and to throw some different flavor in.
Went with 1600Mhz RAM cause you said you'd be playing games, and games have very little increase from high frequency RAM, also gave you a little more SSD space. And a larger PSU for future upgrades a ways down the road.
PS: Gave you Win 7 per request.