A very good $580 build that will be able to run games very well.
PCPartPicker part list:
http://pcpartpicker.com/p/1XIzN
Price breakdown by merchant: http://pcpartpicker.com/p/1XIzN/by_merchant/
Benchmarks: http://pcpartpicker.com/p/1XIzN/benchmarks/
CPU: AMD FX-6300 3.5GHz 6-Core Processor ($109.99 @ Newegg)
CPU Cooler: Cooler Master Hyper TX3 54.8 CFM Sleeve Bearing CPU Cooler ($17.98 @ OutletPC)
Motherboard: Asus M5A78L-M LX PLUS Micro ATX AM3+ Motherboard ($44.99 @ Microcenter)
Memory: Crucial Ballistix Tactical 8GB (1 x 8GB) DDR3-1600 Memory ($55.25 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($59.98 @ OutletPC)
Video Card: Sapphire Radeon R9 270X 2GB Video Card ($205.66 @ Newegg)
Case: NZXT Gamma Classic (Black) ATX Mid Tower Case ($29.99 @ Amazon)
Power Supply: Corsair Builder 600W 80 PLUS Bronze Certified ATX12V Power Supply ($54.99 @ Microcenter)
Total: $578.83
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-11-05 07:32 EST-0500)