Still running a 2500k at a moderate overclock of 4.5 and I have no reason yet to upgrade. For gaming it doesn't make any sense yet. There just aren't very many games that tax my CPU or even make me want to try and increase my overclock.
Well there are some games that cripple the 2500k. Like Crysis 3 and Planetside 2 for starters. But most games are not an issue. A nice monitor will definitely be my next upgrade. Something like the Swift. Then when I realize that my 680s aren't enough to keep up, I will probably get the flagship 3rd gen Maxwell THEN a CPU.
I run Crysis 2 with the HD texture pack without issue as far as I can tell. What kind of crippling effects can I expect when I get Crysis 3? Are we talking a few less fps or real issues running the game?