There was a post on The Economist about e-books recently, and the author said something that rang true with me. The gist of it was that publishers and booksellers want readers to believe that purchasing an e-book is the same as purchasing a physical book and that they are persistent objects rather than something disposable. I agree with the author that this is something of a hallucination.
Long-time readers of this blog know that I don't buy many books. However, when I do purchase a book, I want it to be something in my hands that I can lend to someone else or refer to whenever I want without worrying about whether my reader device is working. I have had a computer in my house consistently since 1988, which means that I have lived through many format changes and device failures. I'm still mourning the loss of the Amy Winehouse album that is sitting on the hard drive of the laptop that failed over two years ago. I'd rather not go through the same thing with books that I've purchased.
As much as I enjoy having digital access to all kinds of information, I have come to the conclusion that there are some areas where I prefer some sort of physical media in my hand. If I really like an album, I would still buy it on CD. I will probably rip that to play on my Zune, but it is comforting to know that I have a backup. If there is a text that I think I will want to access repeatedly, I would much rather buy it in book form. That doesn't mean that I wouldn't consider buying and using a Kindle if a reasonable system for free borrowing of e-books from my library ever came about. However, for books that I own, I don't want to worry about whether my device can still read the bits and bytes years from now.