I had a huge upgrade itch recently, realised there was no games I needed the upgrade for and that I could run things as I wanted so didn't bother. Best time to upgrade is not when you get the itch but when you notice it's going to make a decent difference and there's some games you want to get the card for.
I would've like a 980ti but when I thought about it I figured I'm better off waiting. Next series of cards will undoubtedly be better (die shrink, better dx12 support, hbm2 and hopefully more vram as standard). They'll be worth the wait but the question is just whether you're able to wait or need it now in which case there's no need to worry about the future just yet. Even on 1080p you're going to struggle to max everything unless you wait for next series.