Another reason to be very wary of replacing paper with something as proprietory as the Kindle is that file formats keep changing - there would be problems if thousands of books only existed as the etext equivalent of Betamax, with DRM controls in place that made it impossible to transfer them to more recent formats, and no way to get them unlocked because the company that owned the technology had gone out of business.
I'm not saying that this is likely for Amazon, but I really doubt that anyone has got the technology completely right, or will do any time soon. It's all going to go obsolete, probably sooner rather than later. It's happened with Betamax, laserdiscs, and probably in the near future ordinary DVDs; anyone who bought HD DVDs or players in 2006-8 is facing that problem now. It happens with all computer games sooner or later; and will undoubtedly happen with the current e-text formats.
A quote that I probably haven't got completely right: "This little baby is going to replace CDs soon. That means I'm going to have to buy the White Album again." - Men in Black
