Of the ones that I have read so far, I particularly recommend muflax for his entirely-logical craziness (Ontological Therapy was awesome), and Yvain for all kinds of interesting, funny, and/or generally awesome posts (exhibits: interesting, interesting, funny, funny, generally awesome - and there are many more that I could have included but didn't).
Related to: Wikifying the Blog List
LessWrong posters and readers are generally pretty cool people. Maybe they are interesting bloggers too. And I'm not just talking about rationalist material, that we'd ideally like to be cross posted on LessWrong, no gardening blogs are also fair game. I'm making this a discussion level post so more people can see the list. Please share links to blogs by former or current LWers. Surely the authors wouldn't mind, who wouldn't like more readers? Original list here.
Anyone who wants to suggest a new blog for the list please follow this link.
Blogs by LWers:
List of LWers on Twitter
Note: Anyone just digging for interesting blogs they would like to read but dosen't care if they are written by LWers or not should check out this thread or maybe this one. Did you guys know we have a wiki article with external resources? We do. Check that out as well. Maybe once we figure out which LWer blogs related to rationality on this list are particularly good we can add a few of them there too.