as the title says... i've got a 55 gallon tank... what type of fish should i throw in it???

i've got a salt water set up if i want ot go that route, but my dad had one and it was nothing but hassle for him.

i think i'm gonna stick with freshies for now.. so what are some bad fish.. mildly aggressive. i want to buy them as babies and watch them grow..

i like most cichlids.. but i'm looking for something with more color. let me know what u think. or what u have if u've got anything!