This is the only real reason I have to buy a Tablet PC. A couple years ago I had the use of a tablet for a couple weeks to develop a proof of concept product. 90% of the time I ended up using it to take notes in meetings. You can scribble down notes like you would on a normal piece of paper, but then easily share those notes with other people. Plus, if you realize that the way you have drawn your diagrams interferes with your notes, you can just "move" them to another part of the page. Same thing goes for if you need to insert another line/word/page in your notes. There was an article on /. earlier asking if there was a point to a Tablet PC, and I believe that yes, there is, but only when it comes to taking notes in meetings.
Ironically enough, at the same time I was messing around with the Tablet PC, I was testing another product called Liquid Office that aimed to create a paperless office.