I currently have an I7 930 @2.8 running with a single 580 sc.
I am planning on picking up a second 580sc and throwing them into a x16/x16 SLI.
Would my cpu bottleneck anything here?
Also, what if I threw in a 780 instead of runing 2 580s in SLI? Would the cpu bottleneck there?

If you leave your CPU at the default speed you will have a slight bottleneck. If you have a more than adequate 3rd party CPU cooler such as a Corsair H80 or H100 then you can overclock the CPU much higher and increase your FPS.

I wouldn't even worry about spending anything extra for a heatsink upgrade. The bottleneck would be very small, based on threads i read back when the 580's and first gen i7's were somewhat newish.
 
If you're worried about losing a couple percent of your video cards potential, just overclock your cpu to 3ghz or so and check to make sure temps are ok. I ran my i7-920 at 3.2ghz on the stock heatsink before upgrading and my temps never exceeded 65c (minus stress testing) which isn't even close to the threshold.
 
In all honesty you more than likely wont even notice the slight bottleneck anywhere other than benchmarks. But as the other poster said, you would receive more from a newer and/or OC'd CPU than the bottleneck your cpu MAY cause on the 580sc.

Awesome, thanks for the input everyone. I am going to pick up a cooler since it will come in handy later and I will OC my 930 3.2 with my SLI'd 580 scs

ZROCKMAN

DrNinja :  As mentioned , your 930 will function a bit better even without an upgraded CPU cooler @3.0ghz ~ 3.5ghz , plus you can try out some subtle RAM timings that will help as well.   Some other 920 users have overclocked over 4.0 ghz - but they are experienced and knowledgeable.  Most times , it's the North & Southbridge chips that become the problem (overheating) - so they can be used as an indicator , if and when you might have gone too far with something which is going to be the same for long durations.  Especially when gaming.

 
My experience with my i7-920 C0 was that it was fairly simple to get it to 3.4ghz and after that it got quite a bit more challenging. I was able to get it to 3.8ghz and gave up there. First gen 920's are so fun to overclock If you're not willing to do hours of research just search for some 930 or 920 + motherboard overclocking guides and you should be able to get to 3.2 fairly easily. Northbridge overheating was the biggest problem for me, i simply slapped a fan around it and it seemed to make the temps much more reasonable.
 
If you look for guides to overclocking.. make sure you are looking at ones that were posted at least 6-8 months after the cpu's came out. I remember seeing some early guides (on these forums) that suggested i put the voltage on my 920 to 1.46 which thankfully, i did not!

quadlatte

you should be able to hit 3.4 pretty easy, bump the bclk to 166 and pretty much leave the voltages on auto except for the RAM, depending on the specs is were you would set it, but seeing you have dominator GT's i imagine they are atleast 1600mhz chips or higher. I left mine alone and run them at 1333 with 1.59v. temps are very good (high of 60c running IBT on the 20th pass  )  i got it up to 3.8 but my 1st gen H50 cooler is not up for that, so i settled on 3.4. just make sure you have good airflow and cooling not only for the cpu but for the NB/SB chips as well.

Put a couple of Sythe AP-15's on that H50 in push/pull (or your favorite model with decent static pressure) The difference from the single stock Corsair fan is huge.