Also chiming in late, but I'll also endorse the African Flameback Angelfish.
I've had at least three of these fish in various reef tanks and they all did great; no picking at corals whatsoever. My current angel is in my 120gal mixed reef and it's very well behaved. In fact, I think that this fish doesn't even care about anything else in the tank. It doesn't bother any of the other fish or inverts; just wanders the tank looking for bits to eat.
I think it would be a great choice for your sized tank as they are one of the smaller dwarf angelfish species, and the bright contrast of the orange back on the dark blue body is beautiful.
I also like the Genicanthus angels, but they will grow too big for your tank.
I have a Lamarck's in my 120gal that is the dominant fish and there are times that I want to rehome the fish, but it's too pretty to just give it away.
