I've been going through the various options, and I've come to the conclusion that Drupal may well be the best solution for what we'd need for a campus weblogging service. It doesn't have per-blog themes, but that's coming in Drupal 4.6. The rest of the package is rock solid, and the LDAP integration means every @ucalgary.ca could hit the ground running, as Drupal creates weblogs and forums on the fly as users enter the system. That makes administration much simpler for me, and makes the system more flexible for the users.
The first thing I've done is install the SpreadFirefox theme, which looks amazing, but has some quirks with CSS and clear so that some things display only after a LOT of vertical whitespace.
I'm slowly putting together a User Manual, using the Book feature of Drupal. It makes a book into some freakish hybrid of weblog and wiki, with a hierarchical organization of pages and an automatically generated table of contents.
I'm meeting with Paul tomorrow, and we just might decide to roll this out for a limited test period. I'm teaching a class on Friday, to a group of Anthropology grad students interested in new technologies and strategies for teaching and learning. Could be a good fit... :-)