Darksable has the right idea, but since that is over you budget, here is just a little price trimming at no cost of performance.
PCPartPicker part list:
http://pcpartpicker.com/p/3rmxS
Price breakdown by merchant: http://pcpartpicker.com/p/3rmxS/by_merchant/
Benchmarks: http://pcpartpicker.com/p/3rmxS/benchmarks/
CPU: Intel Core i3-4130 3.4GHz Dual-Core Processor ($118.97 @ OutletPC)
Motherboard: Gigabyte GA-B85M-D2V Micro ATX LGA1150 Motherboard ($59.32 @ Amazon)
Memory: Corsair XMS3 8GB (2 x 4GB) DDR3-1333 Memory ($62.99 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($54.98 @ OutletPC)
Video Card: EVGA GeForce GTX 760 2GB Video Card ($239.99 @ NCIX US)
Case: Fractal Design Core 1000 USB 3.0 MicroATX Mid Tower Case ($24.99 @ Newegg)
Power Supply: EVGA 600B 600W 80+ Bronze Certified ATX Power Supply ($39.99 @ Newegg)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($89.98 @ OutletPC)
Monitor: Acer G236HLBbd 60Hz 23.0" Monitor ($109.99 @ Newegg)
Wireless Network Adapter: Rosewill N900PCE 802.11a/b/g/n PCI-Express x1 Wi-Fi Adapter ($24.99 @ Newegg)
Keyboard: Microsoft 3XJ-00001 Wired Ergonomic Keyboard ($16.17 @ B&H)
Mouse: Gigabyte GM-M6800 Wired Optical Mouse ($12.54 @ NCIX US)
Total: $854.90
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-04-13 23:13 EDT-0400)