Not a well thought out question, but I think I understand what you are asking.
Couple of factors.
60Hz at 60 FPS is ideal in your situation. However, you may not always see 60 FPS depending on the game engine and settings. 1920x1080 with a GTX970 or 980Ti is fairly easy for the card to handle right now. A few years from now that may no longer be the case. So, depending on how often you upgrade your GPU you might be better off spending more now.
Upgrades are generally done in two ways. Buy the fastest available and upgrade irregularly, or purchase mid-range products and upgrade frequently. A third option is to sell a GPU whenever a faster product comes out (you are always making a loss, but you can think of it like leasing a car) Since you recoup some of the losses each time your overall spend isn't that much. Buy $500 card, sell for $400, buy a new $500 card, etc.
If you intend to keep that monitor and GPU for a long while and play more or less the same games you have now, then you would not ever need to upgrade.