You know, there is going to be a new game in town if libraries jump on it. The
Freading service (from Library Ideas)
It is a "pay per read" service where libraries pay per checkout. This is available in DRM epub only, so good news for Sony/Nook users. All titles are always available (no waiting lists) and Kindle users can't use it. (Back to Adobe Digital Editions for this). Not that it matters to the rest of us that Kindle users can't participate, because there are no restrictions on how many can circulate at a time. Users are limited by a token system.
Good news for libraries, too, they have a great urban lit selection.