Plan on putting any corals in it? If not, you can go with something in the trigger or tang family. Clown triggers are nice, but can be aggressive. Blue Hippo or Yellow Tangs are OK for your tank. Also a green bird wrasse or lunare wrasse. A porcupine puffer is cool. If you want aggressive, get you a nice volitan lion (just watch out for the quills if you put your hand in the tank). 80 gallons can maintain up to three or four 4" - 6" fish, or six to eight 1" - 3" fish. This site has pretty much any of the fish you can buy for your tank. Just decide whether you want a docile, semi-aggressive, or aggresive tank, then go from there.