Since I live in the middle of Wyoming, I didn't have the chance to try either one out. So, I bought both with the intention of making my decision after test-driving them.
I chose the
-The Kindle's screen was crisper.
-I liked the feel of the Kindle better.
-The Nook showed up with a bum battery. I know I could have gotten this replaced, but it didn't make me feel great about the Nook. (Also, since then, a friend with a Nook had the frame crack. B&N mailed her a new one, but this doesn't seem to be a rare issue. Perhaps because the Nook's frame is all one piece of plastic and the Kindle has separate buttons for page forward, etc.?)
-Since I don't live close to a B&N, the freebie books in the store weren't something that mattered to me.
-The Kindle was easier to navigate even though the Nook has a touch screen. The touch screen was really slow.
-The lending feature on the Nook was cool, but only lending a book once for two weeks at the most didn't overcome the other issues.
-The Kindle works with audible.com, which is where I get many audio books.
I really agreed with this article about the differences between the two. I think I just liked the feel of the Kindle better, though that certainly plays in with the crispness of the screen, the frame buttons, and the navigation that I mentioned.
I'm definitely glad I tried them both so I was sure I got the one I wanted.