The lavenders are exquisite in a subtle sort of way. At first glance many think of them as drab but if you stop to think, they wouldn't call them lavender if there wasn't some purple in them. And the more you look at them, the more you see different colours flash out from them. They're definitely one of my favourites, and at 8" max size they are a nice small tang too (especially for Acanthurus sp.).
Here's an interesting article about them:
http://www.hawaiisfishes.com/fish_of.../fom_05_03.htm