Not trying to step on shred5's info, but wanted to add this about anthias. Long read, but definitely worth it for the information on anthias...
http://www.liveaquaria.com/PIC/article.cfm?aid=266
That is actually a good read. I find it pretty much dead on..
If you want a shoal, ignitus and dispar seem to be the best.
I have ignitus which are pretty hardy once established but dont ship well.
They are very hard to get to eat dried food but are not hard to get on frozen food like cyclopeese, mysis and their favorite Calanus. They are very agressive eaters. They need lots of feedings though. They have very little aggression between each other. Dispars are about the same as ignitus in pretty much every way.
I also have lyretails which are aggressive as can be. They do not shoal together. My male does shoal with my ignitus so If I were to do it again just one lyretail. Lyretails dont shoal normally in a reef tank. They are very hardy and can get away with 3 or 4 feedings. They are aggressive eaters and I had them on very small pellets in a week. In smaller tanks they are sometimes hard to keep multiples because sometimes they beat up on the smaller one till it dies and so on.
Another hardy one is bartletts but again I would only keep one. They all seem to turn male and fight.
Resplendent Anthias and Randall's Anthias are another good choice. I dont have allot of experience with these but make a great choice in a smaller reef. They are a little harder to keep but are hardy once established. These seem to shoal but not as much in open water. They seem to stick a little closer to the rock work.
Most people have not had issues mixing some species too.. Just one male to a species though.
Anthias like fast moving water..
I think what is great about most anthias is they like the open water mostly. They also seem to bring the other fish out some.
The deeper water anthias will some times hide or look for cover from the bright lights they also can be harder to keep.