Despite of the pros and cons of getting a good gaming 4k monitor or those 34" 1440p 21:9 curve IPS GSync monitors, for now, I would recommend to stick with a 1440p 144Hz IPS monitor with GSync, since you have a GTX980Ti.
e.g. ASUS PG279Q or Acer XB2711HU
A 1440p 144Hz 16:9 IPS monitor with GSync is at the moment the most overall attractive solution for hardcore gamers.
Those monitors are like having the perfect balance of refresh rate/speed, resolution, image quality and price for today. (I know that the price is still extremely premium for most of us)