As per some other folks. I'd also consider dual 690's a bit pointless. I think anand did some testing and there's a noticeable lack of improvement as you add more.
If we are simply going to throw money at a build as it's available stick the big revodrive in there. It will make the machine fly in a much more noticable way than the 2 extra GPU cores will.
Revodrive, 2x moderately good 500GB SSD's in raid 0 on a Z77 board. i5 chip. 16GB RAM (you do NOT need more for gaming. With about 3 GAMES running it's hard to break 8GB even) etc. Build a decent machine rather than something for the price.
Not getting an i7 in that build is ridiculous, future games are using more and more cores. Also the more GPU's the better they scale with more CPU cores, bf3 especially.

















































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. The 7990 should theoretically have the edge for higher resolutions and highr levels of AA due to it's 384-bit wide memory bus (compared to nVidia's 256-bit bus), but i don't think it makes too much difference with current games.
Surprised no one bought up EVGA dual CPU mobo....