Actually, It varies. Usually the more formal churches are more strict about using old Catholic-like titles like "Father" and even "Mother."
But some really don't care if they are informal. At my old church, we were pretty laid back. I actually called my minister "Marsha." (Her first name.) Mind you, it was a 50 person church and everyone was basically friends.
In the Episcopal Church anyway, there are a billion names you could call a pastor. Vicar, Priest, Minister, Cleric, and "Priest-in-charge." I usually called my 1st pastor a "minister."
While Priest tends to be most associated in the Catholic Church, it's also commonly used in the Orthodox Churches. (Greek, Russian, ect.)
Anglicans/Episcopalians are probably the only Protestants that will ever accept it. I'm not aware of another Protestant denominational that uses it.