Here you go:
PCPartPicker part list:
http://pcpartpicker.com/p/QFQvPrice breakdown by merchant:
http://pcpartpicker.com/p/QFQv/by_merchant/Benchmarks:
http://pcpartpicker.com/p/QFQv/benchmarks/CPU: Intel Core i7-3820 3.6GHz Quad-Core Processor ($229.99 @ Microcenter)
CPU Cooler: Corsair H80i 77.0 CFM Liquid CPU Cooler ($88.98 @ Amazon)
Motherboard: Gigabyte GA-X79-UP4 ATX LGA2011 Motherboard ($233.99 @ Amazon)
Memory: Corsair XMS 64GB (8 x 8GB) DDR3-1333 Memory ($369.99 @ Best Buy)
Storage: Samsung 840 Pro Series 512GB 2.5" Solid State Disk ($463.23 @ Amazon)
Video Card: Gigabyte Radeon HD 7970 3GB Video Card (3-Way CrossFire) ($389.99 @ NCIX US)
Video Card: Gigabyte Radeon HD 7970 3GB Video Card (3-Way CrossFire) ($389.99 @ NCIX US)
Video Card: Gigabyte Radeon HD 7970 3GB Video Card (3-Way CrossFire) ($389.99 @ NCIX US)
Case: Corsair Obsidian Series 800D ATX Full Tower Case ($273.99 @ Amazon)
Power Supply: Corsair 1200W 80 PLUS Platinum Certified ATX12V / EPS12V Power Supply ($299.99 @ Microcenter)
Optical Drive: Samsung SH-224BB DVD/CD Writer ($16.98 @ Outlet PC)
Operating System: Microsoft Windows 7 Ultimate Full (32/64-bit) ($288.00 @ Adorama)
Total: $3435.11
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-04-14 15:33 EDT-0400)
Of course, this system is overkill, by far, for mining.
It's also overkill for gaming, unless you have three 1440p monitors that you want to game on simultaneously.
And 64 GB of memory is overkill unless you are doing things like image process, rendering, etc.