I'm looking for a good intel cpu to last till the haswell maybe even skylake release, I was thinking of skipping Ivy bridge (not much boost in performance over sandy bridge?) at the moment I primarily game, however as a chemistry undergrad i'm not sure if ill need the extra power of the 3930k, I understand that in terms of gaming performance the difference between the two processors is merely non-zero, however i'm looking for some longevity.
I think Chris summed it up nicely in his 3930k review --
"If you’re gaming with one (or even two) high-end graphics cards in your system, doing a lot of desktop productivity work, or simply on a more constrained budget, the -2600K is a better bet. Shoot, at that point, I’d still say step it on down to a -2500K."
Any processor over 400 dollars does not provide appreciable return to warrent its cost. The price difference could get you double the ram and an SSD, which would zip things along much more appreciably.
The 3930K and SandyBridge Extreme is a sale gimmick parading around a meek set of chips and passing them off as high end on a watered down server platform. Socket 2011 is as useful as a turd sandwich, and the price to performance is rather pathetic.