it depends largely on what type of tank you want to have (reef, agressive, comunity -Fish Only, Fish only with Live Rock (FOWLR), etc)
Maybe look at dwarf angels (they are peaceful, don't mix with agressive fish - check them out) I think the best looking is the flame angel, but they also have the coral angel, lemonpeel, etc.
I have a 45G (FOWLR), anf plan on having 1 flame angel as my 'prize' fish, and then a bunch of other colorful fish to go with it (green mandarin dragonet and false percs for sure, I'll decide on more later)
HTH
Brian