This should suit you
PCPartPicker part list:
http://pcpartpicker.com/p/uUKg
Price breakdown by merchant: http://pcpartpicker.com/p/uUKg/by_merchant/
Benchmarks: http://pcpartpicker.com/p/uUKg/benchmarks/
CPU: AMD FX-6100 3.3GHz 6-Core Processor ($99.99 @ NCIX US)
Motherboard: MSI 760GM-P21 (FX) Micro ATX AM3+ Motherboard ($49.99 @ Mwave)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($49.99 @ Newegg)
Storage: Seagate Barracuda 1.5TB 3.5" 7200RPM Internal Hard Drive ($69.99 @ NCIX US)
Video Card: Sapphire Radeon HD 7770 GHz Edition 1GB Video Card ($111.97 @ Newegg)
Case: Cooler Master HAF 912 ATX Mid Tower Case ($49.99 @ NCIX US)
Power Supply: Antec High Current Gamer 620W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($69.99 @ NCIX US)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($22.98 @ Newegg)
Monitor: Acer G205HVbd 20.0" Monitor ($89.99 @ Newegg)
Keyboard: Logitech K120 Wired Standard Keyboard ($9.93 @ Amazon)
Total: $624.81
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2012-12-29 22:29 EST-0500)