A very rough estimate:
i7 2600K: $315
2 GTX580: $850
LGA1155 mobo: $200
OCZ 1000W modular: $200
16GB of RAM: $100
An SSD: $100
A 1TB drive: $60
Use whatever you have left for a case and optical drive
So I'd say you can run a pair of 580's. You can save a couple 100 by running a pair of 6970's and spend the extra on a new monitor/cooling solution/etc.
1) Mainly gaming
2) $2000 for just parts
3) NJ
4) total new build, may have a monitor or use it on a 42" HD TV
5) NA
6) no overclocking
7) currently have a 21"
8) building it asap
9) USB 3.0, would prefer amd video
10) will be buying win7 64bit