Permalinks Screwed Up
The permalinks are screwed up right now. That is the one problem I have had that keeps me from 100% satisfaction with WordPress -- the mod-rewrite stuff is pretty finicky and can lead any custom permalink structure to get screwed up from time to time.
Update: Fixed now. There is some kind of bug that whenever I try to change the URLs of categories, I get a permalink mess. So I am just creating redirects for all the old category locations and calling it a day. This error may well be a host problem rather than a WordPress problem.