Nothing is "future proof." I wish I could find the thread; one of my fellow moderators pointed out that the highest-end card from five years ago (gave model) can't play most current games. You can build a machine that won't need to be replaced quite so soon, but it will eventually need to be replaced unless, like me, you gave up gaming and only use it for browsing, office apps, and software development.
That said, the more money you pour into your graphics card the longer it will be able to keep up with the "current" games of the time. But you could buy one step down, save a third of the money, and put that 1/3 away against having to do a new build four years from now instead of three. In the long run, that's less expensive.
So it's your choice: Given that any rig will become obsolete in at most seven years, how much are you willing to spend now to push that date out six months or a year? I personally choose never to pay the premium for the latest and greatest, given that in less than a year it will be merely good.