Perhaps instead of a semi-fixed selection of blogs there could instead be a some sort of Reddit/Hacker News like way for users/editors to submit and vote on particular articles. That way we'd be able to pick up an occasional good post from a blog full of pet photos, or drop irrelevant ones from mostly good blogs. More work, but more useful.
I'm spending the summer working to update lesswrong, and one of the changes we're looking to implement is changing the "New on Overcoming Bias" part of the sidebar to a more general "New on Rationality Blogs". What blogs would you like to see represented?