I am big fan of great user interfaces. I have written before about how interface design progress has been severely stunted by the web. I happen to think that PDAs, the only widespread users of consumer touch screen technology have been severly stunted by the BlackBerry. I know people who use them, love them, but seriously... it can't be because of their user interface.
Here is some really intersting progress on the touch screen front sent to me by ceilingtiles. Check out the movie demo.
Multi-Touch Interaction Research