[Incubus]

I have a Kindle 3, and while its not as large as the DX, I'd say it was still a good alternative to the real thing, but it depends a lot on how you want to read the book.

If you read the book from cover to cover then it'll be great. If you want to look up specifics in the book, then it'll be great for that too thanks to the search.

On the other hand, if you want to flick through the book reading the parts that interest you then paper is still much easier to use.

As for an iPad, I can't see how it would possible be any better than a dedicated ebook reader for reading programming books. I'd stick with my Kindle.

[frou_dh]

I disagree about the Kindle 3. Its screen is physically too small to be good for information dense pages. PDFs are especially bad because their layout isn't reflowed, meaning you must X-Y pan around with the plasticky buttons.

I like my Kindle 3, but for reading I think it is only suitable for novels and plain prose. I actually use the web browser a lot. It's terrible, but it's free! (3G data, no fees or contract)

[jon_hendry]

"On the other hand, if you want to flick through the book reading the parts that interest you then paper is still much easier to use."

True, but you can make this work a bit better by setting up bookmarks. If a book has a table of contents that links to the chapters, that would make it easy to set up bookmarks for each chapter, that can be accessed from the menu.