Ok, I don't own an Amazon Kindle yet, but my neighbor got one the day before Thanksgiving (like two days after the product was announced). He works at Microsoft, go figure he was able to get one before me :)
And I wouldn't call this too much of a review... just wanted to jot my thoughts down for others as this is still a pretty rare product.
Anyway, he brought it to our Thanksgiving gathering and showed it off to me. I was really impressed overall with its capabilities.
The Amazon Kindle is about the size of a "regular" book, and thus fits nicely in your hands. The eInk display is excellent and exactly as advertised - easy on the eyes, easy to read. The user interface takes a little getting used to, but once you are used to it its pretty intuitive. It has "next page" and "prev page" buttons on the side of the unit within reach of your thumbs. And its scroll bar is separate from the actual page display - it looks like a mercury thermometer. There's a dial to scroll up and down. Again, takes some getting used to, but once you have the hang of it it works nicely.
The ability to search the downloadable book library is easy to use and fast, and navigation through the titles on the devices is easy as well. And in addition to books you can subscribe to newspapers. My neighbor already had the WSJ and Seattle Times on it, and navigating through both of those were easy.
It also provides a web browser, and while not overly impressive it would suffice nicely for web browsing while traveling - as good as Microsoft Windows Mobile, with the down side that sites probably aren't going to render specifically for the Amazon Kindle browser.
The one complaint I had was the amount of time it takes to render a page. Upwards of a second by my calculation. Doesn't seem like a lot, but I expected it faster and I expect users do as well. Oh yeah and the design was, well, uninspiring. But that's ok for me. I don't buy products for cool design, I buy them for their functionality.
I can see myself getting this soon. As soon as enough book titles that I want are available :)