Comparing music(ipods, mp3s) with books is really a broken comparison. The first reason is that switching between an album, CD, and mp3 I have the exact same experience. Reading a digital book and a paper book are still very different experiences to me. Physical books have advantages over digital books, no batteries, better type, the ability to read during take-off and landing, etc. CDs vs. MP3s are basically the same on all of those fronts.

You also have to factor in that books are usually single use, which means more people will go to the library or give their book away when they are done reading it. This is all legal now, as soon as it's digital they will become criminals?