Stock fans are fine, aftermarket fans just generally look better and perform slightly better. Nothing huge, people just like having them. A chrome/metallic theme is bit tricky. Can't really think of anything.
As for 4k monitors, you mean like January right? Probably nothing huge, though you might get to see a few deals around the holidays.
Also this is on MassDrop right now https://www.massdrop.com/buy/lg-27-4k-freesync-monitor-27ud68p-b?referer=XJLUKT
though FreeSync won't work with Nvida GPU's. Not a bad thing, you just won't get to use the FreeSync part.