Well, any current i5/i7 quad core in the 3ghz+ range, or a current AMD in the 4ghz range should do quite nicely in combination with any performance video card made in the last few years.
As a general rule, you should avoid anything that isn't the top end or second stringer when it comes to a video card.
If you're getting a series 9 Geforce, the 960 is already so weak that it barely outperforms a 680 in most things, actually does worse in some. The 950 is just a dog. If you want to get a 4k monitor and do gaming at that resolution, your only serious options are a 980 Ti or a Fury X, nothing else has the power without running multiple cards, and that leads to game specific performance and display issues.