Philosophia Naturalis, the blog carnival for the physical sciences.
The Splintered Mind, on philosophy of mind and psychology.
Think Tonk, on miscellaneous philosophy.
Marginal Revolution, on miscellaneous topics loosely related to economics.
Dinosaur Comics, where T-Rex explores bold new ideas on a daily basis.
Tim Krabbe's Chess Diary, for chess curiosities.
I have also deleted several links to blogs that have died, or that have stopped interesting me enough to keep the link. Also eliminated links to Technorati, Wikipedia and the Arxiv, which I never used (because I have them stored in Favorites) and neither did my readers (presumably for the same reason).