I don't know what CPU I should buy

Hi! I'm currently planning to build a new high end gaming pc. I'm definately about to future proof it, going with the new gtx 1080 (not the founders ed. though) but I'm unsure what cpu to match it with. I mainly play wow, which I've heard is cpu dependent and I really want to play the new wow expansion coming this fall on ultra settings. What is the smartest choice? Since I know close to nothing about building pc's I just assumed the i7-6700k was the top notch cpu. Is this a correct assumption? Additional info. I don't plan to OC. I do play lots of other games as well, everything from indie games to AAA titles and prefferably, I'd like to run those at ultra as well. Oh, and if it matters at all, I'm doing no video editing what so ever!

Greatful for all kinds of feedback! :)