Apple Font Book is OK for a small font collection of a few hundred fonts, but nowhere a professional app.
Linotype Font Explorer Pro is the best font management software by a large margin. Has all important features, is stable, and quite fast. It also provides font activation plugins for Adobe and Quark apps.
My FEP setup is as follows. I organize my fonts myself in 16 font style categories, which range from Black Letter, Humanist Sans, etc., to Slab and Symbol. In FEP I created identical font style categories as smart sets with the following rule: Comment begins with [Name of style category]. Hence to group a newly imported font into the right style category, I just add the category to the font's comment section, and also rate the font with 1-5 stars. If you have many fonts, this setup will allow you to find suitable fonts much faster via styles and ratings. And you can sort fonts by style and rating, too.