Best configuration for animation and rendering starts (and stops!) with your budget.
After that you look at what hardware best suits the software you are going to use.
It's not always about buying the best computer your budget will allow. If you're talking about freelance or contract work (earning income) you might want to be thinking about a render farm cluster of several less expensive computers. This can help you be a lot more productive when you're not tying up your animation workstation with long, time consuming rendering runs.
Part 1. Your animation workstation
Part 2. Your rendering computer(s)