What is your budget? Are you attempting to playing 1080p @ 60 FPS? Name a few games you wish to play. What are your full specs, including your power supply's manufacturer and model #.
Addendum: But personally I don't think I'd bother upgrading unless I was going for at least a GTX 980, and I haven't liked that card as an upgrade option, since the release of the 980 Ti. Now that they are $500, a 980 Ti is something that I would consider. But since the 1080 (non-Ti) is more powerful, similar money and more energy efficiency, that's what I'd go for. I'd get the GTX 1080, assuming the price is close to the $500 range upon release. Otherwise, I'd get a 980 Ti if I couldn't wait another day. For the 980 Ti, you'll want a tier 1...