PCPartPicker part list:
http://pcpartpicker.com/p/1ng9N
Price breakdown by merchant: http://pcpartpicker.com/p/1ng9N/by_merchant/
Benchmarks: http://pcpartpicker.com/p/1ng9N/benchmarks/
CPU: AMD Phenom II X4 965 Black 3.4GHz Quad-Core Processor ($92.13 @ TigerDirect)
Motherboard: MSI 970A-G43 ATX AM3+ Motherboard ($65.01 @ SuperBiiz)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($68.99 @ NCIX US)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($59.98 @ Outlet PC)
Video Card: Sapphire Radeon HD 7770 GHz Edition 1GB Video Card ($89.44 @ SuperBiiz)
Case: Raidmax Atlas ATX-295WB ATX Mid Tower Case ($24.99 @ Newegg)
Power Supply: Corsair Builder 500W 80 PLUS Certified ATX12V Power Supply ($44.99 @ Microcenter)
Optical Drive: Asus DRW-24F1ST DVD/CD Writer ($16.00 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($89.98 @ Outlet PC)
Total: $551.51
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-08-01 22:25 EDT-0400)