I haven't OC'd my CPU yet. I was thinking about it not too long ago but figured I'd get much much more out of a new GPU and didn't really know how it would affect the whole build. Pretty happy I bought the 2500k when I did, probably the best component purchase I've ever made. People seem to still say pretty much only positive things about it even when it's a couple of years old.
The MSI 970 seems to be the cheapest/most sold item pretty much everywhere at 390€ + a Ubi game (too bad I already bought FC4 since that's the only interesting game of the three, probably just end up selling the game to a friend). Don't see many complaints about coil whine or other problems in the reviews either so I think I'll go for that one even if it's a lot of money. I like instant noodles and canned tuna anyway.