I had an Anularis Angelfish years ago and has been my absolute favorite fish ever. Great personality...really a cool fish. Blue throat Trigger was a close second (look cool and not as aggressive as most triggers).
For some of the others, I think you've gotta look at various sites. The Tusk, for example, will probably have different sizes on different sites. LiveAquaria, as someone else mentioned, seems to go larger. I am no expert, but I am thinking that while larger can't hurt, slightly smaller ( with most fish) can't be that detrimental. I do agree with the 6' rule on most Tangs though.
I use Bluezoo, Vividaquariums and LiveAquaria as references and also have a couple LFS
that seem to know what they are talking about.