$700, prices won't be the same in a month, but this is a good starting point. If you want to go Intel instead, look into a Z77 board with a i5-3570k. If you want to stretch the budget I highly recommend a GTX760.
PCPartPicker part list:
http://pcpartpicker.com/p/1owDi Price breakdown by merchant: http://pcpartpicker.com/p/1owDi/by_merchant/ Benchmarks: http://pcpartpicker.com/p/1owDi/benchmarks/ CPU: AMD FX-6300 3.5GHz 6-Core Processor ($109.99 @ Newegg) Motherboard: Asus M5A97 LE R2.0 ATX AM3+ Motherboard ($74.99 @ Newegg) Memory: PNY 8GB (2 x 4GB) DDR3-1866 Memory Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($80.98 @ Newegg) Video Card: Asus GeForce GTX 660 2GB Video Card ($193.98 @ Newegg) Case: BitFenix Merc Alpha (Black) ATX Mid Tower Case ($49.99 @ Newegg) Power Supply: XFX 650W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($79.99 @ Newegg) Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.99 @ Newegg) Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) ($99.99 @ Newegg) Total: $698.90 (Prices include shipping, taxes, and discounts when available.) (Generated by PCPartPicker 2013-08-05 13:45 EDT-0400)