Future-"proof" is a myth; there's no such thing, and four years is a long time. That said, an i7-4770K is probably about as future-"resistant" as you're going to get. I'm sure it will be viable for far longer than four years.
we havent seen any major performance-increase in the newer desktop generations.
With this said, we could be looking at a longer period of time without the "need" to upgrade.
But as always this is only guessing.
Like the first comment said nothing is really future proof but the i7 4770k is the closest you are going to get for right now but soon they will be releasing DDR4 memory and quad channel memory will become a standard. As long as AMD is still making low end CPUs Intel will not need to put forth the effort of doing any major improvements on their processors.