I recommend two recent meditations on the present and future roles of rare book libraries and special collections:
The Library in the New Age by Robert Darnton, incoming director of the Harvard University Library (New York Review of Books, June 12, 2008).
Meditations on the Beinecke Rare Book and Manuscript Library, a talk given by the Beinecke's director Frank Turner, on Jan. 8, 2008 at the Grolier Club.
Both Darnton and Turner argue that today's digital information world makes rare books & manuscript collections more important, and not simply as mines for content creators.
Several of my favorite "oldies but goodies" in this vein are by Daniel Traister at the University of Pennsylvania.
Finally, two blogs worth checking out:
BibliOdyssey, dedicated to "Books - Illustrations - Science - History - Visual Materia Obscura - Eclectic Bookart", is a consistently satisfying feast for the eyes and the mind, as well as an instructive exercise in data mining. The curator, Paul K. of Sydney, brings together an incredible variety of graphic material in books, manuscripts, advertising, and ephemera from around the world.
Rare Book Librarian