A page really worth your time and energies as a summary of a lot of metadata issues and practicalities: http://metamanagement.comm.nsdlib.org/IntroPage.html

The A-Z of Thesauri may be useful in thinking about the issues of controlled vocabularies for various specialties, mentioned at the last meeting.

The Crosswalks intro article is another efficient springboard, and the Library of Congress "Core Metadata Elements" seems like it addresses a lot of the questions some have about how to handle non-book materials, especially in the section on metadata levels.