The i7-4770k will last longer, assuming that game developers start taking advantage of the hyperthreading. Still, I'd pick the i5-4670k. You'd get similar results for 3 years, and then you'll want an upgrade anyway. Maybe to a nice 16-core running stock at 5GHz, we'll see
OK, I have a 4770k myself, but I do a lot more than gaming on this PC.