I edited FP4's build a little and came up with this:

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-2500K 3.3GHz Quad-Core Processor ($169.99 @ Microcenter)
CPU Cooler: Cooler Master GeminII S 69.7 CFM Sleeve Bearing CPU Cooler ($48.47 @ NCIX US)
Motherboard: Biostar H61MGC Micro ATX LGA1155 Motherboard ($54.98 @ Newegg)
Memory: G.Skill Value Series 8GB (2 x 4GB) DDR3-1333 Memory ($39.99 @ Newegg)
Hard Drive: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($64.94 @ B&H)
Video Card: Sapphire Radeon HD 6870 1GB Video Card ($164.98 @ Newegg)
Case: NZXT Source 210 (White) ATX Mid Tower Case ($45.98 @ Newegg)
Power Supply: Antec 550W ATX12V Power Supply ($54.99 @ SuperBiiz)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.99 @ Newegg)
Total: $661.31
(Prices include shipping and discounts when available.)