Help me build a computer

I have the budget of around $700 and need a computer build,
I either want the build to have a 660TI or a AMD 7970, you can choose what one to put in.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: AMD FX-6300 3.5GHz 6-Core Processor ($109.99 @ Newegg)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.98 @ OutletPC)
Motherboard: Gigabyte GA-990FXA-UD3 ATX AM3+ Motherboard ($129.99 @ Newegg)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-2133 Memory ($63.75 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($58.99 @ NCIX US)
Video Card: Gigabyte Radeon R9 280X 3GB Video Card ($305.91 @ Newegg)
Case: Cooler Master HAF 912 ATX Mid Tower Case ($49.99 @ Microcenter)
Power Supply: OCZ ZT 650W 80 PLUS Bronze Certified ATX12V Power Supply ($49.99 @ Newegg)
Total: $773.59
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-10-30 23:08 EDT-0400)

Best I can do on your budget. Even though it's over budget, but I refuse to use terribad parts. Although you could replace the motherboard I chose with this one http://pcpartpicker.com/part/asus-motherboard-m5a97ler20 I just don't like 970 Chipsets, not as good quality as 990FX mobo's.
R9-280x IS a 7970 GHZ Edition just rebranded, with slightly better quality parts.

Up your budget to $800 and upgrade the CPU to an AMD 8320 and the build is perfect, however the AMD 6300 is adequate for gaming as only a few games like Crysis 3 utilise all 8 cores.