PCPartPicker part list:
http://pcpartpicker.com/p/j5U8
Price breakdown by merchant: http://pcpartpicker.com/p/j5U8/by_merchant/
Benchmarks: http://pcpartpicker.com/p/j5U8/benchmarks/
CPU: Intel Pentium G850 2.9GHz Dual-Core Processor ($69.99 @ Newegg)
Motherboard: ASRock H61M-DGS Micro ATX LGA1155 Motherboard ($44.99 @ Amazon)
Memory: Patriot Viper 3 8GB (2 x 4GB) DDR3-1600 Memory ($28.99 @ Newegg)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($58.88 @ NCIX US)
Video Card: Sapphire Radeon HD 7850 1GB Video Card ($176.97 @ Newegg)
Case: Cooler Master Elite 430 ATX Mid Tower Case ($29.99 @ Newegg)
Power Supply: Corsair Builder 500W 80 PLUS Certified ATX12V Power Supply ($39.99 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($90.37 @ Amazon)
Total: $540.17
(Prices include shipping, taxes, and discounts when available.)
Made it $9 cheaper. I don't know how you feel about mail in rebates. It should be exactly $600 now.