General Question - Best Theme to Support Network

[sator]

I am trying to improve my site and take it to the next level. Basically, I want to have a front page that will post new articles on developments within a special niche subject but I also want people to interact via our social network (using Buddypress). Members will be eligible to create their own sites (within the Wordpress Multisite install).

What I would like to do is have these various sites sorted according to sections - a general category for the type of sites being created on the network. For example, Classroom sites, Organization sites, various Features of the site (wiki, dictionaries, general repositories of information).

Which theme would be best for pulling a listing of these sites according to some kind of organization feature?