I spend a lot of time thinking about and working on the interactions between physical paper and electronic paper, hence, I guess, two types of paper. But there's another way that I'm not 'normal' — I use a Tablet PC.
Two things reminded me of this recently.
The first was a comment on, I think, the BBCs Digital Planet, that Tablets are great but are only widely used by academics and people at Microsoft. If my recollection is correct, the theory was that using a tablet is very different from using a keyboard and most people have invested so much time in learning the idiosyncrasies of keyboard and mouse that other input mechanisms, like the tablet, have a big barrier to entry and so haven't gone mainstream in the way you might expect.
[At this point I'm likely to digress into a story about Palm Graffiti and how my regular handwriting began to take the same form...]
The second was the interest I got in using the Tablet at a three day standards meeting. Comments ranged from 'cool' to 'weird'. What was particularly impressive was that, having completely flattened the box the day before flying out to install a clean Vista SP1, the handwriting recognition was excellent even without running through the personalization process. Now that is cool 🙂
If you ever get a chance to play with a tablet, I recommend it — just be prepared to invest a little time and effort.