I may be dangerously falling into "if you have WP every problem looks like a blog" but I need tasty and easy to use front-end for hobby/collaboration site. I had covered features required and what had failed already in details over at my blog, won't repeat here.

So my draft idea is WordPress + P2 theme + wiki plugin (I think there are some around).

Should I bother with looking into BuddyPress? Zero experience with it and as I understand it requires WPMU installation as well. I think I read WPMU is getting integrated in main WP branch - what it means for BuddyPress?

Should I be looking at related projects at all, maybe clean WP will be enough to handle small group?

Any good examples of site that are already doing what I want to do with WP?

TIA for any advice, overall I am in early planning stages so need loads of info to choose good direction.