Here's a brief overview of what you should be looking at. You might want to look at the thread in my signature and give us the missing info.
CPU: i7-920 $289
Mobo: Asus P6X58D Premium $310
RAM: G.Skill PI Series 3x2 GB 1600 mhz CAS Latency 7 $180
HDD: Samsung Spinpoint F3 1 TB $90
Optical: Cheapest SATA DVD burner $24
PSU: Corsair 850W $130 after rebate
Case: HAF 922 $100
GPU: HD 5870 $400
OS: Windows 7 $100
CPU Cooler: Coolermaster Hyper 212 $30 (if you want to overclock)
Total: $1,653 after rebates. Didn't look for any combos, but I'm sure they're there. That leaves almost $350 for the monitor, keyboard and mouse.