Just to clarify a minor point, it's "first sale"[1] not "fair use" that gives libraries the right to circulate books, dvds, etc.

It seems that the immediate that CC licenses will do for libraries is that it'll let patrons do more stuff (i.e. beyond fair use) with the CC resources we make available to them. And it'll let us do more stuff ourselves, with those same resources. And of course, we could eventually license our own content under CC...

[1] http://en.wikipedia.org/wiki/First_sale_doctrine