If you start off with 4GB RAM it gives you more money to spend on the video card. You can always add another 4GB later. I threw in a much better motherboard too.
PCPartPicker part list:
http://ca.pcpartpicker.com/p/3Q4Zr
Price breakdown by merchant: http://ca.pcpartpicker.com/p/3Q4Zr/by_merchant/
Benchmarks: http://ca.pcpartpicker.com/p/3Q4Zr/benchmarks/
CPU: AMD Athlon X4 750K 3.4GHz Quad-Core Processor ($79.97 @ Amazon Canada)
Motherboard: Asus A78M-A Micro ATX FM2+ Motherboard ($63.75 @ Vuugo)
Memory: Kingston Black Series 4GB (1 x 4GB) DDR3-1600 Memory ($39.99 @ Memory Express)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($59.99 @ DirectCanada)
Video Card: EVGA GeForce GTX 750 Ti 2GB Video Card ($149.99 @ Amazon Canada)
Case: Xion XON-560 MicroATX Mini Tower Case ($39.99 @ Amazon Canada)
Power Supply: Antec EarthWatts Green 380W 80+ Bronze Certified ATX Power Supply ($48.50 @ Vuugo)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($16.79 @ DirectCanada)
Total: $498.97
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-05-24 13:47 EDT-0400)