I keep thinking about the Kindle. The $400 price is the main drawback, but reviews like this one might put me over the line:
If possible, I love my Kindle even more than I did when I reviewed it a few weeks ago. I've got about 50 books on it, and I love always having something with me to read. I also love the ease of using it one handed, and checking my email from anywhere. As far as I'm concerned, it's better than a book. The biggest downsides are that not everything I want to read is on it yet, and conversely, that it's awful easy to spend a hell of a lot of money browsing. But there's so much cheap content from the public domain that this is not a huge issue.
But I'm also waiting for that one device that will do it all -- online, phone, computer, media player, pda, etc., etc. Maybe Kindle 2.0 or 3.0 will be it, and I should wait.