This is what I would do, as it has the CPU and Mobo you selected, plus a faster harddrive, a the same type of GPU, but included in a combo. Also, I love the NZXT Gamma case is a good low cost option, but for not much more this Corsair case will blow it out of the water. The PSU is a also a proven in the budget builds.
PCPartPicker part list:
http://pcpartpicker.com/p/rRXe
Price breakdown by merchant: http://pcpartpicker.com/p/rRXe/by_merchant/
Benchmarks: http://pcpartpicker.com/p/rRXe/benchmarks/
CPU: Intel Core i3-3220 3.3GHz Dual-Core Processor ($109.99 @ NCIX US)
Motherboard: ASRock H77M Micro ATX LGA1155 Motherboard ($69.99 @ Newegg)
Memory: Mushkin Blackline 8GB (2 x 4GB) DDR3-1600 Memory ($39.99 @ Newegg)
Storage: Western Digital Scorpio Black 500GB 2.5" 7200RPM Internal Hard Drive ($69.99 @ Mac Mall)
Video Card: HIS Radeon HD 7850 1GB Video Card ($176.97 @ Newegg)
Case: Corsair 200R ATX Mid Tower Case ($49.99 @ Newegg)
Power Supply: Corsair Builder 500W 80 PLUS Certified ATX12V Power Supply ($51.98 @ Newegg)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($17.89 @ Outlet PC)
Total: $579.79
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2012-12-10 16:43 EST-0500)