PCPartPicker part list:
http://pcpartpicker.com/p/3HmHS
Price breakdown by merchant: http://pcpartpicker.com/p/3HmHS/by_merchant/
Benchmarks: http://pcpartpicker.com/p/3HmHS/benchmarks/
CPU: Intel Core i3-4130 3.4GHz Dual-Core Processor ($119.97 @ OutletPC)
Motherboard: MSI H81M-P33 Micro ATX LGA1150 Motherboard ($49.99 @ Mwave)
Memory: G.Skill Ripjaws Series 4GB (1 x 4GB) DDR3-1333 Memory ($38.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($54.44 @ Amazon)
Video Card: EVGA GeForce GTX 650 1GB Video Card ($99.99 @ Newegg)
Case: Linkworld 617-03-c2228U MicroATX Slim Case w/400W Power Supply ($34.99 @ Mwave)
Optical Drive: Lite-On iHAS124-14 DVD/CD Writer ($14.99 @ Newegg)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($89.98 @ OutletPC)
Total: $503.34
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-05-10 11:38 EDT-0400)
It's actually cheaper than yours without the mail-in rebates. Better CPU, GPU is 50% stronger in benchmarks. I did go with a case with a built in power supply to save money though. (Not recommended in my opinion to do so unless you don't plan to upgrade) Could've easily stuck with your RAM and saved $3, but Kingston compatibility issue with voltage.