I own the Kindle 2. If you ask me to choose again now, I’ll still go for the Kindle instead of the Nook and the Sony Reader, because I think the web browsing function is rather important (the Nook and Sony Reader does not have a web browser). The free internet (and now it is free international internet) plus the web browser allow me to look for information whenever I’m in need. It is really a cool feature that cannot be missed. And right now it is free for both the U.S. and many other countries, it is just incredible when you bring it to trip.

I like to use the text-to-speech function on the Kindle too, meaning that I can "read" with my hands and eyes free… This function is only available for the Amazon Kindle. There are more and cheaper ebooks you can find available for the Kindle too.

There are some good comparison between the Kindle and the Sony Reader here:

http://www.amazon.com/gp/redirect.html?ie=UTF8&location=http%3A%2F%2Fwww.amazon.com%2Freview%2FR3ULAFVHBGYVQP%3Fie%3DUTF8%26ref%255F%3Dcm%255Fcr%255Frdp%255Fperm&tag=moreinfo-po-20&linkCode=ur2&camp=1789&creative=390957

http://www.speedreaderxreview.com/kindle-2-0-vs-sony-reader-prs-700bc-comparison

Hope it helps