I7-2600k, maximus 4 extreme-z vs i7-3930k, rampage 4?

From a value standpoint perhaps. That's not to say it's the better option. LGA2011 is without a doubt a better platform. It supports 40 pci-e 3.0 lanes (Over quadruple the current bandwidth of 20 pci-e 2.0 on 1155), support for up to 8-core cpus (3990X) and quad-channel memory.

That's not to say any of those things will make a difference to the average gamer. That's why we have a mainstream chipset and an enthusiast chipset.

Here's a look at the 2600k vs the 3960X, I know this isn't what you were looking for but for whatever reason the comparison tool doesn't list the 3930K. It should be noted that the only real difference between the two is the 3MB less of L3 cache.

http://www.anandtech.com/bench/Product/287?vs=443