Perhaps unsurprisingly due to the coder's tendency to code rather than write about coding, I haven't run into very many good coding-related blogs, and it certainly isn't for not trying; however, over a decent period of time I have found a few that make me tingle with ideas every time I read them.
All Things Pythonic -- Python -- Guido van Rossum: Yeah, he's the creator of the language, and no, he's not much of a speaker at conference; however, even if just for his recent post Five-minute Multimethods in Python, he's got one hell of a blog. Whether they are posts about the future of python or about implementing some concept in python, his posts rarely disappoint.
bramcohen's Journal -- Theory -- Bram Cohen: He's the guy who wrote BitTorrent and a set of other cool apps. His writing comes off a big arrogant, but it is usually quite in depth on a variety of subjects, lately he's been analyzing games.
dive into mark -- Python / Meta -- Mark Pilgrim: Okay, this one shouldn't count, Mark stopped blogging some time back, but if you haven't read his stuff, it is worth digging through the archives. This guy has produced some extremely fine code, the Feed Parser, PyGoogle and PyAmazin just to name a few that are in wide circulation.
/dev/blog -- Mac / Meta -- Amit Singh: Much of it is less code-oriented and more about how to use your Mac to be a better coder. He releases open source software from time to time that is useful, too.
Handwriting on the Sky -- Python -- Glyph Lefkowitz: LiveJournal, the hackers choice? Glyph is the guy behind Twisted, and writes very nicely about python, the coding community, and system-related stuff. He is also quite a nice guy.
webvergnügen -- Mac / Social -- Jonas Luster: How could I leave out Jonas. He writes about plenty of non-coding topics, but never ceases to be on top of whatever neat project is out there. Very interesting blog from all angles.