The fact that biological, or 'natural' rules might help in the creation of a computer generated work of art is interesting, but even a wonderful work of art made in this fashion isn't the same as a...
I think that the most beautiful thing lately hasn't been in hardware or software per se but collaboration - the idea behind Napster, which uses the distributed power of the Internet as its engine.
During the iPod's development process did you get a sense of how big it would become? The way you can tell that you're onto something interesting is if everybody who knows about the project wants one...