My reader is full of worthwhile material, so it's hard to pick, and also I'm a chickenshit and I don't want anyone to get mad at me. But then, it would be kind of chickenshit not to. I know! The ennui! It consumes! I went with anything that qualifies as an insta-click when it pops up in my reader. Here goes:
Best individual blog : dy/dan. Even though Dan went half corporate this year, he keeps feeding me lessons that are made of adolescent catnip. And if you hadn't noticed, is constructing a new framework for math ed.
Best individual tweeter : @msgregson I don't know when this girl sleeps, but she's the most reliably helpful tweeter around. She's going to be a technology coordinator to be reckoned with.
Best group blog : 360. I spend a little time trying to hack my way through some intimidating math blogs, so I enjoy the way these college professors can make sophisticated concepts relatable.
Best new blog : Questions? Dave Cox came out swinging this year, asking profound and demanding questions of his not that new practice. Take a moment to appreciate how rare that is. And he can carry a tune, too.
Best elearning / corporate education blog: Not sure what category works best for Colleen K, but http://www.mathapprentice.com/ and http://www.mathplayground.com/ both blow me away. I know I didn't do anything with my computer degree, but if I had, I hope it would look something like that.
Best resource sharing blog The Exponential Curve Blog posts are sporadic, but Dan Greene figured out how to share all of his stuff, all of the time, and keeps adding to it.
Best teacher blog Continuous Everywhere but Differentiable Nowhere There should be a preservice course about how to improve your practice through written reflection, and a large part of it should be reading Sam's blog.