Extremely dependent, or maybe only dependent, on your budget!
5000\$+: go for iMac Pro.
\$3000 to \$5000: go for Mac Pro,
\$2000 to \$3000: go for 15 inch MacBook Pro.
As you go higher, you have more options to choose for CPU and RAM capacity, i.e.
With MacBook Pro, you only get a maximum of 4 cores with 16GB 2133MHz LPDDR3 RAM.
For Mac Pro you can have 6, 8, or 12 cores with 16, 32, or 64 GB DDR3 RAMs. based on your choice, the price would be different.
With iMac Pro, you can get 8, 10, 14, and 18 cores with 32, 64, or 128 GB DDR4 EEC memory.
Note that as you increase the number of cores, you will get less GHz on each core, as usual!
You can see them on iMac Pro, Mac Pro, and MacBook Pro.
P.S. the more equipped your system is, the more years it will last from a technological point of view. I mean, it will take longer to become obsolete! This is my view BTW and it might not be true, but it comes from my personal experience.