as a general rule, you want a ski that is around the same length as you are tall. Go shorter if anything (with todays skis)
Maybe a bit longer if you are a racer (downhill).
Stuff like GS and slalom use a lot shorter skis.
If you are more a park / jump person, then a bit shorter as well.
If you seek a lot of deep powder, and go off piste all the time, then aim for something around your height with a decent width in the waist (85+)