“By 2010 more than 50 percent of books sold worldwide will be printed on demand at the point of sale in the form of library-quality paperbacks.”

At some point, laptop or smaller devices with high quality displays and suitable access controls for intellectual property will make the sale and consumption of books, sounds and movies through these devices practical. Audio devices, such as Apple's iPod, offer an example. Carrying around a bunch of paper is uneccessary and despite the argument that a book doesn't need a battery or a re-charge, I believe that it will be very common for people to read for work and for pleasure with the same device(s) they use daily to do their work. I don't think books are going away, of course. And if electronic reading devices have not penetrated widely enough on a worldwide basis by 2010, I will lose my bet :)