$750 gaming computer

Chose a fairly expensive case you can swap out for something cheaper :D

http://pcpartpicker.com/p/1TeLd

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-4430 3.0GHz Quad-Core Processor ($174.99 @ Amazon)
Motherboard: ASRock H81M-HDS Micro ATX LGA1150 Motherboard ($52.99 @ Microcenter)
Memory: G.Skill Ares Series 8GB (2 x 4GB) DDR3-1600 Memory ($63.75 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($58.99 @ NCIX US)
Video Card: PowerColor Radeon HD 7970 3GB Video Card ($249.99 @ Newegg)
Case: Cooler Master Storm Scout 2 ATX Mid Tower Case ($89.99 @ Newegg)
Power Supply: Corsair Builder 600W 80 PLUS Bronze Certified ATX12V Power Supply ($39.99 @ Newegg)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer ($14.98 @ Outlet PC)
Total: $745.67
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-10-25 21:39 EDT-0400)

You'd have to factor in the cost of Windows yourself, though
 
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