Considering the AMD/ATI purchase, I wouldn't just assume that there will be one.
It will most likely happen, but if you want SLI, go Nvidia; else go the route of a 3870x2 and an addtional 3x70. Should be freak'n sweet.
Considering your processor is not as fast as a comparable Intel, I dont' think it woudl be far off the mark to have a graphics setup that isn't quite as fast as the Nvidia counterpart (under most tests).
