I like
http://slatestarcodex.com/ a kinda pessimistic leftist who sometimes calls himself a libertarian, but wrote the best takedown of libertarianism I've ever read:
http://slatestarcodex.com/2014/07/30/meditations-on-moloch/
It's what finally pushed me out of libertarianism after it was straining under my increasingly long list of qualifiers. He has a bunch of other great articles too ranging from ADHD to bayesian analysis.