If you want to find out where tablet PCs are going, you should be getting your hands on OneNote. I've used the first release for a little while and it is very good, even though it feels a bit like a Version 0 product. That looks set to change with Service Pack 1. This is not simply a set of fixes for bugs (although there are some in there). It looks to me like a leap in functionality which takes OneNote out of the "fun to play with" category and moves it towards the "part of how you work" one. The interesting thing is that a lot of what it does is equally valuable even if you have a desktop PC.
I've not had time to play with it much yet but but it looks seriously useful. If you want to find out more perhaps the best place to look is the
OneNote Service Pack 1 page. This has a link to a document which you can print out that describes what the product can do. Take it from me, you are going to like it. It looks like we all finally have reasons to own tablets....