^^ Pretty much what he said. I have a 4670k - very quick processor, tweaked it up to constant 4.1ghz and it's a happy camper right there. Only thing is, Haswell is now two generations old, and any upgrading is going to require all-new stuff.
Skylake is current gen, you'll pay a little more for it, but it has an upgrade path for the next few years. Given a choice -now- I would just bite the bullet and get the Skylake setup. DDR4, good overclocking, M.2 drives, more PCIe lanes etc.
It's just a more modern platform to build off of.