PCPartPicker part list:
http://pcpartpicker.com/p/trnjK8
Price breakdown by merchant: http://pcpartpicker.com/p/trnjK8/by_merchant/
CPU: Intel Core i5-4590 3.3GHz Quad-Core Processor ($159.99 @ Micro Center)
Motherboard: Asus H97-PLUS ATX LGA1150 Motherboard ($99.99 @ NCIX US)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory ($59.99 @ Newegg)
Storage: Samsung 850 EVO-Series 120GB 2.5" Solid State Drive ($69.98 @ OutletPC)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($47.89 @ OutletPC)
Case: Zalman Z12 Plus ATX Mid Tower Case ($78.36 @ NCIX US)
Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply ($46.99 @ NCIX US)
Optical Drive: Asus DRW-24F1ST DVD/CD Writer ($17.88 @ OutletPC)
Operating System: Microsoft Windows 8.1 (OEM) (64-bit) ($87.75 @ OutletPC)
Monitor: BenQ GL2460HM 60Hz 24.0" Monitor ($139.93 @ B&H)
Total: $808.75
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-03-05 11:59 EST-0500
Just throw both the R9 270s in there and you're set.