I was thinking, the sunburst dock which was released some time ago was a great idea, and allowed you to change programs while in other programs, well i was thinking considering apple has included a screenshot feature where you can use the wake button and the silent/volume switch...
how about

being able to hold the home button and at the same time use the volume button to change programs kinda like Alt-Tab or Apple-Tab on xp/mac.... what do you think?