im a huge fan of our twinspot hogfish.
http://www.youtube.com/watch?v=61ieeD-eDwM
hes super active and curious, eats like a horse without any fuss, and got along with everything in the tank (although i hear they might go after smaller shrimp or crabs like pom poms). i wouldnt say hes a centrepiece fish but defin rounds out the tank.