I'm thinking about slowly getting ready for 4K video editing. I can do small projects with my current setup, which is a 15" rMBP and a Windows PC (i7, SSDs, 970GTX). I'm running out of disk space and external monitor resolution, and basically everything, so if I'm going to do it properly, I have to upgrade a lot. So, my question to you is, what's your ideal HW & SW setup for editing 4K video? If you already do it, can you share some tips about the workflow?