Skylake may have been interesting if it didn't get delayed so much or if Intel would have chosen to delay Broadwell too. But now BW is already around the corner with SL out. There's a reason why most OEMs ignore SL almost completely...
DDR4 is still pricey, USB3.1 so new that compatible hardware is either buggy as hell, against the standards or doesn't exist yet.
I see no real reason to upgrade/replace now unless your current rig is crapping out or at its absolute limit.