I'm not aware of any blogs that focus exclusively on the Nook - the Nook seems to get featured on a lot of tech blogs, and blogs for people who are e-reader-obsessed, but only Kindle seems to have generated that kind of single-device following. I wonder if it is because Nook uses ADE, so people tend to float across devices because the software is the same?
The Nook obsessed hang out at:
http://www.nookboards.com/forum/
http://bookclubs.barnesandnoble.com/...ds/ct-p/eBooks (official B&N forums but there are some very knowledgeable people there)
http://nookdevs.com/