Imo several of the builds here are a bit unbalanced.
My suggestion:
PCPartPicker part list /
Price breakdown by merchant /
Benchmarks
CPU: Intel Core i7-3770K 3.5GHz Quad-Core Processor ($324.99 @ NCIX US)
CPU Cooler: Noctua NH-D14 65.0 CFM CPU Cooler ($75.98 @ Outlet PC)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($114.99 @ Newegg)
Memory: G.Skill Ares Series 16GB (2 x 8GB) DDR3-1600 Memory ($79.99 @ Newegg)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($99.99 @ NCIX US)
Storage: Samsung 830 Series 128GB 2.5" Solid State Disk ($96.49 @ B&H)
Video Card: Gigabyte Radeon HD 7970 GHz Edition 3GB Video Card ($413.78 @ NCIX US)
Case: Corsair 600T ATX Mid Tower Case ($133.56 @ Mac Connection)
Power Supply: Corsair 850W ATX12V / EPS12V Power Supply ($114.99 @ Newegg)
Optical Drive: Samsung SH-222BB/BEBE DVD/CD Writer ($16.98 @ Outlet PC)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($90.85 @ Amazon)
Keyboard: Microsoft SIDEWINDER X4 Wired Gaming Keyboard ($47.52 @ B&H)
Total: $1610.11
(Prices include shipping and discounts when available.)
(Generated by PCPartPicker 2012-08-30 11:29 EDT-0400)
I'm not American, but I've heard that you can get a nice discount on your CPU + motherboard if you live close to a microcenter shop. That should bring the price down to approx 1550$.
Some comments:
-Don't go watercooling. The Noctua NH-D14 should give you similar performance at a lower price.
-You can definitely afford 16GB of RAM.
-The 7970 outperforms the GTX 670 in most games, and here it's just as cheap.
-A 850W PSU will handle 2x 7970s. The 680 is not worth it nowadays because the 7970/670 performs similar at a much lower price.
-No need to get a 256GB SSD. Storage does not affect games' performance, only loading times, which you shouldn't care about (they're still very fast on fast HDDs).
EDIT: Other alternatives to bring costs down (I cba to calculate exactly how much they bring the costs down):
Drop the CPU to a 3570K (I would advise you to stay at the 3770K in your budget)
Newegg 3770K + Extreme4 combo deal
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.1029178
Newegg TX850W V2 + Extreme 4 combo deal (better saving than the above 3770K + Extreme4)
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.1029178