A lot of responses to this depend on the perspective of the responder, and what they hope ebooks can achieve.
The most disappointed folks seem to hope that ebooks will take over, and paper books will go away. I don't see that happening, and wouldn't want it to.
For me, ebooks are an additional format to paper, and not a replacement. Each format has strengths and weaknesses.
I like ebooks because I can carry a library in my pocket and always have a book to read, and because content in electronic format is searchable, which is handy for reference material and technical manuals.
But there are some things that ebooks don't do well. Consider art books. You need color and high resolution, and you need a large display area to properly present the art. You don't have that in current dedicated readers, since eInk devices aren't currently available in color, and you'll never have the display space on a handheld device.
And while I'm as green as the next person, I do have to point out that trees are a renewable resource. If you want to save trees, your daily newspaper is a much better place to start.