I really freaking love it.
Since I got it about a month and a half ago, I've read seven books on it. I have bought a few and found lots of free books online. I've gotten those free e-books both from the Amazon Kindle page and Project Gutenberg.
Getting books from Amazon is super easy. Ridiculously easy. Getting the ones from Project Gutenberg requires a couple more steps, but is also a quick and painless process. (Nook users can also use Project Gutenberg. It has book files in many different formats.)
I took my Kindle with me when I traveled to Georgia earlier this month. Anytime I travel, I end up taking lots of books. This trip, I took two paper books and my Kindle. I actually had room in my suitcase for other stuff and lots of reading choices on the Kindle.
Another plus about the Kindle is not having to hold it open like a regular book. It's very easy to read in bed or while eating since all you have to do is hit the next page button.
And one feature I thought was unnecessary, but find really helpful: the dictionary. You can move the cursor to any word on the page and a definition will pop up. I'm surprised how much I've already used it.
Overall, I'm thrilled with it. I was skeptical before I got my Kindle, but it's totally won me over. I LOVE it.