Fish in my 24g Aquapod: Clown (false perc), yellow clown goby, yellow watchman goby, blue chromis and a six line. They are all great but I think the six line is our current favorite.
I have a coral beauty in my 55, but keep in mind that they don't have a good track record if you plan to keep SPSs, at least that's my understanding. The one in my tank leaves my softies alone. I'm also not sure how he would be in a smaller tank, liveaquaria recomends 30g minimum so you could be okay. I think mine would be unhappy though.