A few things:
1. Don't forget RAM. 16 GBs is the sweet spot right now for capacity. Specific CAS timing, latency, and frequency speed will be dependent on your CPU selection, which leads me in to my next point;
2. Overkill on the CPU for what your stated use case is. You can get a 4 or 6 core CPU for half the price from either AMD or Intel that will run fine for your stated use case.
3. Great selection on a GPU, but it's not likely going to be easy to acquire any time soon. Same goes for the comparative GPU from AMD. Something to keep in mind.
4. You're gonna need a bigger SSD. 256GBs is going to drop to 200GBs instantly once you've installed your operating system. Look for a 1TB if you plan on doing anything else besides playing a handful of games.
5. The motherboard isn't wifi capable out of the box, so you'll need to either plug in an ethernet cable or purchase a wireless network PCI-E card in order to connect to the internet.
Lastly, I'm assuming you already have case fans, a computer monitor and peripherals (mouse, keyboard, wi-fi adapter, etc.).