DeanMSands3 69 Junior Poster

I'm struggling with a side-scroller platformer game engine I'm working on. I want to provide Actors (primarily monsters) with state machines to follow, but I'm worried about how best to implement them.
Right now, Actors extend Entities (I'm still torn on whether passive Entities like items/scenery should have states) and I've created an ActorState class, but my creative thought process ends there.
Some states a monster might have are:
Melee Attacking
Ranged Attacking
Taking Damage

The plan that occurs to me is to create state-machine maps for classes of Actors (like Melee-Non-Flying Monsters, Ranged-Aerial Monsters, etc., etc.) I'm still unsure.
Has anyone here approached this problem and how did you resolve it?