Depends largely on what you shoot and your shooting style/preference. If you are using 1.5x/1.6x body, the 85mm may be slightly too long for indoor portraits. 50mm would give a wider FOV.
For general purpose portraits on a crop body, the 50mm would probably be a good choice. YMMV. Best is to try out both lens first before taking the plunge. (that is what I would normally do...borrow or rent out to try first).
As for 85mm vs 70-200mm 2.8, I would say both lens can co-exist in any set-up, since they serve different purposes. The 70-200 for range, and versatility, the 85mm for speed (larger f-stop) and low light situations.