I remember when I first started up my 75 gal--I recieved advice from this site to stay with fish that will not grow bigger than 6-7 inches--Looking back now, I think that is very good advice.
I really love my foxface lo--there's a nice magnificent foxface at liveaquaria.com that I would love to get if I didn't already have a foxface. Clowns fit this size, also dwarf fuzzy lion (great fish!). Lemmonpeel angels are supposed to be beautiful. I think you would need to stay away from puffers, triggers and large angels.
My .02 worth of ideas....