I have been dealing with pen based computers for nearly 10 years now. TabletPC is pen based computing done right, closer then it has before anyway. Some don't get the advantages of pen based computing. The biggest argument that is heard is that I can type faster then I can write. Well no kidding. Anyone that spends 15 hours a day in front of a keyboard should be able to type fast. Ink and speech are called "alternate" input, not the only input. Ink is just another way to interact with your computer. If you look at in that way, then you can start to see some of the advantages. I am using a Toshiba M200 and I really like it. This is a convertable model, and for general use, convertables are the way to go. I use the keyboard 90% of the time. I use inking when I'm in meetings and brainstorming ideas. I think it is very rude and annoying to be in a meeting and be typing notes. I have always used pen and paper to brainstorm out new ideas and designs. With the tablet and software such as OneNote I can still use the same method that I have been using for years, but now I have a searchable version of those random notes and thoughts. What's even better is that you can email these random thoughts and meeting notes and get further input.
There is still a big hole for software that really takes advantage of the TabletPC. Vertical markets will be the first to really utilize the TabletPC. We are going to be rolling out 7000 of then at the start of next year. As the price and technology of the digitizers improve, TabletPCs should start moving into the mainstream market.