Hi there! I work as Nuke compositor and lately I've been studying Houdini at home. I want to upgrade my old i7 3770, 8gb ram, GTX 750ti for a new machine. I will do procedural modeling, simulations, lighting and rendering in Houdini, as well as some Nuke and Maya.
This is a list I got that could work as a starting point:
Not sure about your rendering setup, is it GPU or CPU? At any rate, bumping up the CPU to 1950x is a good call if you have an option. CPU is utilized for many things by many nodes, can't go wrong with that decision. Other than that, solid setup.
I heard recently that the GTX 1080 Ti cards might be dropping in price with the release of the next generation cards, it might be worth looking into whether waiting a little while might save you some money.