Blogs
What the heck does "blog" mean anyway? Is there an exact definition?
I only check out a couple of them regularly, including Andrew Sullivan's, and Jerry Pournelle's (which may not be technially a "blog.") The others I usually find through other links on specific subjects. If I read all the interesting ones regularly, I wouldn't get anything else done all day.
Would the Wall Street Journal's "Best of the Web" qualify? How about NASAWatch? I also use these as regular sources.