This is the game I decided to build my first desktop PC for. After gaming a couple of years with an Alienware m17x laptop with a 7970m (which is still pretty powerful, I ran DA:I at high / ultra 1080p with around 40-45fps), I decided that I would need to build a new rig in order to get the best experience with this game. Which is something that I had been thinking of doing anyways.
All in all, my choice of GPU for Witcher 3 couldn't have been better seeing as I'm using a GTX980. I couldn't be more pleased that I'll be able to max out this game using hairworks and have more than enough headroom to install graphics type mods. I'll probably go into the .ini file to enable everything that I can't enabled via HUD too.
Also, I don't get people saying a 980 is a waste of money. For a little bit more money, you can futureproof your PC a lot better than you can with a 970.
I call it an investment well spent.