At D4, Sony CEO Howard Stringer showed off the new Reader, an electronic book that looks like something a real person would actually want. The Reader is very thin, lighter than a real book, and employs a backlight-free high-contrast display technology that makes text easier to read than on any other lightweight device I've seen. I'd line up to buy one if it'll cost less than the $300 Stringer mentioned in his interview.
The issue with e-books, of course, is content. Sony is still working out the details of selling books. (Hopefully, the electronic versions will cost less than physical ones.) The device will also support PDF files. Personally, I hope it has a good RSS reader so that I can use it to catch up on my blog reading during my daily streetcar commute.