Jeff Han, from NYU's Computer Science department is giving a demo of something called Multitouch, a new computer interface. he has a rear projection graphing table with a multitouch sensor, something not normal on a touch screen. You can do chording, for example.
He shows a fluid simulation (lava lamp) that responds to multiple touch. You can easily see how you can do things to the interface that you can't do with a single point of touch (like a mouse).
He demos a photographers light box application. Picking up pictures, rotating them, etc. is exactly the same as doing it in real life and it's intuitive. Pulling on the display (spreading your hands apart) zooms and pushing does the opposite.
He mentions the 100 dollar laptop and that we might be introducing people to a mode of interaction that is unnatural.
He contrast this with Minority Report's gestural interface and one based on touch. Tactile feedback is more intuitive than gestural interfaces for casual users.
He can bring up a keyboard, of course. The question is, should you emulate a physical keyboard closely? There's a danger in freezing design too fast.