In blogging as in most things, I prefer the timeless to the transient. I read history books, not newspapers. And if a blog entry won't be interesting in a month or a year, I'd rather not write it.
In this spirit, I just came across two posts from Catallarchy that past the test of time. Check out Trent McBride on the AMA and drug prohibition, and Scott Scheule on how to strike a quixotic blow for economic literacy.
I have a nomination for timeless econ-related blogging, though for opposite reasons of the Catallarchy posts: Arnold's prediction of perfect spherical diamonds so cheap they could be used as fuel in a woodstove.