If gaming is your priority (since you listed it first) get the 6700k. I doubt you'll care about the extra 2-10 minutes of rendering or like another half hour of compressing (if you're talking 200GB).
Get a cheaper mobo aswell since i don't think you need the 200 euro mobo.
But the 6800k will be some sort of future proofing for future apps that your going to do / cpu intensive games
Personally id get the 6700k and spend the other cash for a gift to my parents but either are good, just one side will have more money
I don't know much about the developing software so i won't say anything though but just for my curiousity, what are you developing?
Edit: if your going x99 might aswell get quad channel ram and not dual