Although i gave you an option i think 2xGTS is a mistake youd be better off with a single GTX or even stick with 1xGTS and when the G92 comes out grab one of those with some of the money you saved on the second GTS.
If you get a single GPU you would also be better off with an intel P35 chipset mobo
Gigabyte DS3L for $101 at newegg and buy a eVga GPU, so you can use the 90 day upgrade option when the new ones come out soon!! And yes, I would go with the single card option that chookman used. 1 GTX would be better than 2 x GTS's.