For $800 go for something like this.
CPU: Intel Core i5 2500K
Mobo: Asrock Z68 Extreme3 Gen3
RAM: G.Skill-NT 8GB (2x4GB) DDR3-1333
HDD: Samsung Spinpoint F3 1TB
GPU: 1GB AMD Radeon HD6950
Case: Antec 100
PSU: Antec Neo Eco 520C
ODD: LiteOn DVD burner
CPU HSF: Coolermaster Universal Hyper 212+
For $1500
CPU: Intel Core i5 2500K
Mobo: Asrock Z68 Extreme4 Gen3
RAM: G.Skill-NT 8GB (2x4GB) DDR3-1333
SSD: Crucial M4 128GB
HDD: Samsung EcoGreen F4 2TB
GPU1: VTX3D 2GB AMD Radeon HD6950
GPU2: VTX3D 2GB AMD Radeon HD6950
Case: Coolermaster HAF912 Advanced
PSU: Silverstone Strider Plus ST75F-P 750W
ODD: LiteOn DVD burner
CPU HSF: Coolermaster Universal Hyper 212+
Lazy atm, got the specs straight off whirlpool. You live in America so parts would be cheaper, so you may be able to squeeze in some better parts like a 2600K, better ram, or an lc hsf.