If you have asparations of doing a reef tank, stick with fish that are considered reef-safe from the begining as save yourself trouble down the road. You have lots of options...a small school of blue/green chromis, royal gramma, firefish, reef-safe wrasses, clowns, gobies, and others. In a 55 with 80lbs of LR
you should be able to start with a pair of percula or ocellaris clowns with no problems. They are common and popular fish, but are a lot of fun to watch and add nice color to the tank.