Definitely have to agree with @Hyboria about the SSD & PSU recommendations. I'll also add that you might want to consider getting an R9 380 instead of the GTX 960: you can get 4GB models for the same price (or even $10-20 cheaper), & in most games there's a 5-10 FPS improvement in performance -- TechSpot shows superior performance in newer games like Rise of the Tomb Raider, Star Wars Battlefront, & Tom Clancy's The Division, although for some reason the 960 wins out in Fallout 4.
To be honest, I'm not sure there's a point in getting a wireless adapter for this desktop PC. Unless it's going to be located somewhere that doesn't have easy access to an Ethernet cable, & especially if it's located in the same room as your router, you would be better off just using the onboard RJ45 connection. If you really do need one, though, then unless your home broadband connection is faster than your Wireless-N router's speeds, you probably don't need a Wireless-AC-compatible adapter; on the other hand, they're apparently pretty close in price (maybe an extra $5-10), so if you need wireless might as well go for the most current standard.
CPU-wise, it can depend quite a lot on the game. Again, Fallout 4 shows the i3-6100 trouncing the FX-83xx chips, but in Star Wars Battlefront it flips the other way, while The Division & Rise of the Tomb Raider don't show much variation in CPUs (where not only the FX chips but also the i3s are able to keep up with Haswell & Skylake i7s). On this one, it really comes down to the particular games you'll be playing, so that you can look at the benchmarks.
That being said, you might want to consider a 990FX board instead of a 970 board. They usually have some extra features over the 970 chipsets -- for example, my board can not only handle 2-way CrossFire but also handle 2-way SLI (something the 970 boards can't do), as well as having 2 eSATA ports should you want external storage. They're not too much more, either (the Revision 5.0 version of my board is only about $30 more than your selection).