http://pcpartpicker.com/p/2G1fz
PCPartPicker part list:
http://pcpartpicker.com/p/2G1fz
Price breakdown by merchant: http://pcpartpicker.com/p/2G1fz/by_merchant/
Benchmarks: http://pcpartpicker.com/p/2G1fz/benchmarks/
CPU: AMD FX-8320 3.5GHz 8-Core Processor ($149.99 @ TigerDirect)
CPU Cooler: Cooler Master Hyper 212 Plus 76.8 CFM Sleeve Bearing CPU Cooler ($27.97 @ OutletPC)
Motherboard: MSI 970A-G43 ATX AM3+ Motherboard ($65.91 @ Newegg)
Memory: G.Skill Sniper Series 8GB (2 x 4GB) DDR3-1866 Memory ($76.50 @ Newegg)
Storage: Seagate Barracuda 3TB 3.5" 7200RPM Internal Hard Drive ($99.99 @ NCIX US)
Video Card: Asus GeForce GTX 760 2GB Video Card ($249.99 @ NCIX US)
Case: NZXT Source 210 (White) ATX Mid Tower Case ($45.98 @ Newegg)
Power Supply: Corsair CX 600W 80+ Bronze Certified Semi-Modular ATX Power Supply ($54.99 @ Microcenter)
Optical Drive: LG GH24NSB0 DVD/CD Writer ($15.99 @ Microcenter)
Total: $787.31
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-01-22 23:53 EST-0500)
I wouldn't go with a 660 sli as you'd be stuck with no upgrade options at all.