Here is what I came up with pretty quickly:
https://pcpartpicker.com/list/BMxbZ8
A lot of these parts can be changed out as you see fit, but this is what I recommend keeping.
The i7-7700K: It is the consistently the most effective gaming CPU once it is overclocked.
A high end Z270 based Motherboard: For overclocking and supporting M.2 storage.
The 1080Ti: Most powerful consumer GPU at the moment, one will still struggle with two monitors at that resolution, so you may need to add another.
The SuperNova G3: This is an excellent PSU that will power everything you need. Since you are spending so much, a top quality PSU is essential.
The 960 Evo: Since you are coming from a Mac, you have probably gotten used to PCI-E based flash...