General modeling, physics and real-time engines benefit from fast CPU cores. Simulations and CPU rendering benefit from more cores. Viewport performance and GPU rendering benefits from a fast GPU.
The best CPU option I think would be an 8700K (if you can find one), just because Ryzen lacks that extra bit of leverage when doing lightly-threaded tasks. It's pretty much hard-locked to 4Ghz unless you luck out, while the i7 can go to 4.5Ghz or more no problem, as long as you have a beefy cooler on it like a D15 (air) or a Celsius S36 (water).
For GPU there's good reason to consider anything GP102 because Nvidia enabled Quadro-tier optimizations in the latest drivers for them, which means 1080 Ti, Titan X(gen2) or Titan Xp will get much better performance in a variety of situations. That said, you probably won't make full use of it if all you're going to do use Maya and Houdini for animations, so maybe wait for the 1070 Ti.