Gosh, this feels just like April of 2012...
I've been waiting for a long time for Apple to release a Mac Pro that's suitable for professional use. The trash can doesn't count; at this point it's ancient, but more importantly, it's never had an upgrade path. So once again my largest MacOS expenditure is likely to be directed at non-Apple hardware.
I'd like an X299 platform, preferably with on-board 10G ethernet. And while my graphics needs are fairly modest by modern standards, I want space for at least 2 discrete GPUs for machine learning applications. As usual, I want watercooling (for noise reduction). Outside of the GPUs, the only PCI card I should need is the osxwifi card that's in my current hackintosh (for fully compatible bluetooth and wifi for Handoff, etc.).