While I have a Kindle, with a variety of books both non-fiction and fiction, I have found it difficult to use for technical books, because not enough of the "page" is displayed at one time. Furthermore, as others have mentioned, it's hard to jump into the middle of the e-book. That's why I still buy a lot of technical books. BUT, I would consider buying an electronic "summary" of a hard-copy book, that perhaps summarizes syntax, or summarizes the key points of chapters, to serve as an easy-to-transport reference.

I would also like to see a discount on an e-book when you are buying the hard-copy of the same.