Ok, I'm going to bend the rules slightly as I can't choose between my favourites
First we have the Acanthurus Lineatus
Secondly, Acanthurus Sohal.
Finally, Acanthurus Japonicus.
Problem is, the first two are ridiculously expensive and grow tooooooooo big!

Even for an 8x2x2ft! Am looking out for a Powder Brown (Japonicus) though as the two Regals have now gone.