The iPhone user interface is a fabulous piece of design as one might expect. They got many details right which is harder than it looks. And the screen space doubles as a touchscreen that allows multi-finger gestures in various flavours.
Which is my favourite gesture amongst the tapping, scrolling, dragging, and pinching that tumbles over the touchscreen? I think I like the speed-sensitive scrolling best, because it reminds me of spinning a big wheel of fortune (I know it isn’t a new idea but I like how they did it here).
The zooming through two-fingered pinching is technically nice, but may not be more usable than tapping. For really nice multi-touch interaction, future iPhone designers may well profit from Han’s demo. Custom gesture shortcuts would be nice too.