After discussing diffusion of interesting news at the most recent London meetup, I was planning on asking something like this myself.

Futility Closet is nothing but "interesting stuff". It describes itself as "a collection of entertaining curiosities in history, literature, language, art, philosophy, and mathematics, designed to help you waste time as enjoyably as possible". It has more chess than I personally care for, but is updated with what I find to be novel content three times a day.

Conscious Entities is a blog on Philosophy of Mind. It takes an open position on a lot of questions we would consider to be settled on LessWrong, but I think it has value in a steel-manning / why-do-people-believe-this capacity.

(The categories on my feed reader are "Blogs", "CS", "Dance", "Econ", "Esoterica", "Maths/Stats", "Philosophy", "Science" and "Webcomics". I'd be interested in finding out how other people classify theirs.)