Google Reader is, as of now, my RSS reader of choice. It has the ability to compile not only the blogs I follow, but also to allow me to follow my UC Bearcats' sports teams without having to go searching for articles at multiple sites. It's nice to get the updates right on my iGoogle page as well.
I think that, as a teacher, this is a great tool. If students were using this and their teachers were blogging, then I think that students would be able to get all their assignments, etc. via one place. I don't know how feasible it is to expect teachers and students to use this, but it is an interesting concept.
I am a fan of blogging and of all the tools that make it easier to keep up with, especially RSS Feed Readers.