How will people read all of the books that are being digitized? I doubt that we know the answer to that question yet. Portability is still an issue (i.e., what device can your transfer/port the book to). This spring, I got to see someone with a Kindle and she really enjoyed it. While the buzz has died down about it, it's interesting to note that a person doesn't have to be anywhere specific in order to obtain a new book. No going to a library's web site OR going into a library physically. You can be walking down the street and download a new book to read.
Surely the mass digitization programs are thinking about the Kindle model as a way of delivering their content. Imagine that a University of Michigan (UM) student could be authorized to download and read any digitized book from UM no matter where the person was in the world, using technology model that Kindle uses. That would broaden usage and access.
The Kindle is the only book reader I've seen. Where I am, these devices have not caught on. People are generally shocked to think that someone would read a book on an electronic device. I've read books on my PDA while waiting for appointment and meetings, but that idea seems other-worldly to many. However, Amazon has the clout to make a book reader popular. Maybe it is a train we should jump on?