I've spent a fair amount of time reading martial art blogs. There is a ton of good information out there. From time to time I will add links on my blog to other blogs that I feel are of high quality. I plan on being fairly picky. They do not have to be about Jiu Jitsu but they must convey a positive message about the study of martial arts.
One blog that I have spent quite a bit of time reading is Lori O'Connell's Jiu-Jitsu Sensei blog. She covers a wide variety of topics and from what I've seen, is a very talented Jiu Jitsu artist. I especially like the way she looks at the martial arts. She clearly practices her craft with reality in mind. I don't always agree with everything she posts, but I enjoy her perspectives on lots of different topics.
Check out the blog here. I've also added it to the links section of this blog.