You don't say what your budget is.
If buying new, then I would seriously investigate an iMac 27" 5K. This also takes care of monitor. Very nice, very capable.
If considering a new MacPro, I would wait if you can or find one used.
There are lots of older used mac models that will work great. You don't say what type of camera(s)/format/resolution you will be working in, so how to configure your system really depends on that.