Hi Treeterra, are ou having doubt because of the integrated GPU ? Well, I did a bit of research and I think there shouldnt be any compatibility problems with a GeForce GTX 660. I've seen people build with this mobo and an HD 7970. If you look on the same site you were looking at, PC Part Picker, you can check builds made with this particular mobo and some people build their pc with this mobo and a GTX 640 for example. I think you're good to go!
Hope this helps!
Edit : Wasn't quick enough but oh well.