for 1080p 50-60FPS gaming, this system will be great.
You might consider getting a 2-3TB hard drive just because the price difference wouldn't be much.
With so many options out there, you will get endless opinions about exactly what parts to use but for what you want out of it, it's perfect. Good price for all new parts.
The only thing I would seriously suggest is that you get a used GPU. Right now isn't a good time to sink much money into a new GPU since there is such a lack of innovation unless you spend $1000 or so just on the graphics card. You can easily save more than $100 by getting a used 1060 6GB.
i7 7700kK @4.2ghz
16GB DDR4 3200mhz
GeForce 1080 Ti