Wait for the 7nm Ryzen 2 cpu's ,when these chips come out you can decide to buy the newest one or go for a 2700x for a much lower price .
When u go for a 8c/16t or more you should at least take a X*** mobo because of the better vrm's ,imho is a Asrock X470 taichi a good buy .
A verry good case is the Fractal design R6 ,it has plenty of space ,its silent ,and suberb for watercooling .
On that point i am in the same position ,should i go for the 2600 or wait for the new one ? ,but that's for my seccond rig wich is being used for lan-party's .
My main rig is still with the 1700x OC @ 4GHz ,and in combination with a GTX1060 6G it works fine for me .