I recently updated the "Blogs I read" portlet on the right-nav. I especially recommend Ivar Jacobson's "postcards", which is more or less a blog. Jacobson, who was a key player in the creation of both UML and the Rational Unified Process (RUP), always has interesting and insightful things to say. I especially enjoy his comments on the RUP, which he both defends and criticizes, depending on the topic.
Now if he'd only add an RSS feed ...
bhiggins at us.ibm.com
Ivar Jacobson's postcards