Acanthurus leucosternon, commonly known as the powder blue tang, is a very popular tang and for a reason. It's relatively small size and colorful appearance combined with active swimming and algae eating, make it an excellent choice for any decent sized tank. It can be sensitive when newly purchased, but with clean water and little stress it will acclimate fast. It can be aggressive towards other fish, especially other tangs and food competitors, but once it is settled they usually pose no harm to other fish.
(taken while snorkeling in the Philippines)