Here are some blogs I'm not reading enough:
Teach. Brian. Teach. - Brian Frank is writing quite a bit about how students respond to questions and whether or not they can explain possible misunderstandings that other students might have. He's doing some interesting mining of Khan Academy comments, without watching any of the videos.
Research You Should Know - Raymond Johnson (fellow UNI alum - Go Panthers!) has a long running series where he highlight math education research that is interesting or important. Not all of it is directly relevant to physics teaching, but there is so much good stuff there, it's tough to not get drawn in to it.
Great posts about the physics of music - from the view of a scientist and from the view of a musician. It's neat to see this dialog happen online.
It's Okay to be Smart - This is a relatively popular science link aggregator, but new to me. Some of it is not for me, but I find enough on here that otherwise I would have missed.
Learning About Teaching Physics - An extremely well produced podcast about education research related to teaching physics. I wish they would make more of these!
Enough link dumping for now...