It really is preference. What mountain do you ride the most? What kind of terrain is available there?
I am 5'9" and about 200lbs with all of my gear on. I have a 157 TRS for my "big mountain board" and a 149.5 Arbor Draft for my park noodle. My next board will be a 154-156 "jump" board. Arbor Westmark is what I am going for but I might be getting a Rome Mod.