I am a *big* fan of whiteboards and as such am very happy to read your post.
In my opinion, there is the creativity aspect to a whiteboard that you totally grasped (the Mind mapping addition could be worthwhile too). There is also, and it's very important for me, the concept of *transparency*. I always use whiteboards and take opportunity to share what is on it with the rest of the team and other teams. So everyone feel that they can be part of what's going on, without grey areas. Very powerful tool and message.