Copyblogger is a classic theme that’s very well designed. It doesn’t support all of the newest features (threaded comments, for one), but if you’re looking for a nice, clean, easy-to-read theme, this one deserves your consideration.

I especially like the relatively short line-length for posts; if you are the kind of blogger who writes long posts (or are they dissertations at that point?), this theme will help keep them readable.