Here's a build for your budget. This will max WoW and many more besides
PCPartPicker part list:
http://pcpartpicker.com/p/AkI6
Price breakdown by merchant: http://pcpartpicker.com/p/AkI6/by_merchant/
Benchmarks: http://pcpartpicker.com/p/AkI6/benchmarks/
CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($189.99 @ Microcenter)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.99 @ Best Buy)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($119.99 @ Microcenter)
Memory: Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory ($49.99 @ Newegg)
Storage: Crucial M4 128GB 2.5" Solid State Disk ($107.95 @ Mac Connection)
Storage: Seagate Barracuda 3TB 3.5" 7200RPM Internal Hard Drive ($124.99 @ NCIX US)
Video Card: XFX Radeon HD 7970 GHz Edition 3GB Video Card ($424.99 @ NCIX US)
Case: Cooler Master HAF XB (Black) ATX Desktop Case ($94.99 @ Microcenter)
Power Supply: XFX 650W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($104.99 @ Newegg)
Optical Drive: Samsung SN-208DB/BEBE DVD/CD Writer ($26.98 @ Newegg)
Total: $1274.85
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-01-29 17:22 EST-0500)