The Buddy list is a great idea.

Another thing that I have seen is a pesonalized front page for each forum. Allowing the forum owner (club, group, family, etc...) to have a picture, a set of rules, whatever they want to show people as they enter their forum.

This can also be used as a commercial zone. And even better, a combination thereof. Thus allowing advertising revenue as well as personalization.

Another item is more levels of users:
Admin
Category Moderator - Control to assign forum moderators, create forums within a specific category, etc...
Forum Moderator
User
Guest

Just some ideas!

Thanks,