Amazon Kindle
I love the idea of the Kindle -- buy books anywhere anytime, and when you move, you only have to move one device, not tens of boxes of super-heavy books.
But there are several things I don't like about it, too.
1) DRM - Kindle e-books only work on Kindle devices. If Amazon stops making kindle, you stop having access to *your* books.
2) No "import" feature. I've already bought thousands (yes) of dollars worth of books from Amazon. Do I get free digital copies of those books? No.
3) You can't buy it in Canada, and it doesn't work in Canada 
4) No Annotations - This one is the nail in the coffin for me. I write notes in the margins of all my books. The books are my memories of the books (because I have a poor memory). It would be *amazing* if the Kindle came with a stylus, and you could tap anywhere to just start jotting down notes. And the notes section could expand infinitely, unlike the margins of physical books. It could also have some way of cross-referencing other books (a la hyperlinked annotation).
And if Sprint didn't mind them using all this bandwidth, they could launch "Shared Annotations". Imagine reading a book, and having the option to turn on shared annotation view. You'd be able to read annotations by anyone who had ever scribbled on that page/paragraph/word. By mimicking the web itself, this would become an extremely powerful research tool. Too many annotations to sift through? No problem -- implement a digg style up-vote/down-vote the annotation system. This would enable books to take on lives of their own... growing forever.
Maybe the Kindle3 will do it... but I'm not holding my breath.