I just realized what my favourite kinds of blog entries are. They're ones that explain, in exhaustive detail, the technical aspects of a process or system. This link is a good example: It's an article on one aspect of judging Magic: The Gathering tournaments. Now, I've never played in an MTG tournament in my life, nor do I have any particular intention to. Nonetheless, I find this article fascinating; it's almost totally useless to me, but it demonnstrates that there's a craft to judging (and that some people who've learned the craft are willing to share their knowledge).
I'm trying to think of other good examples -- Joel's articles come to mind, as do some of the explanatory articles on Kuro5hin. Jeremy has the capacity to write those kinds of articles too, when he's not writing opinion pieces. Rands writes more pedagogically than descriptively, but still has that mastery-of-his-craft aspect to the articles.
"So, Fraxas, why don't you write articles like that?", I hear you ask. And the answer is this: they're really hard. And I'm lazy.