In Apple's patent from what I understand there is now an active sensor that recognizes not only a specific device like that prepared stylus but also other things like for example a finger. Neat, esp. when it really works that the sensor really detects the x, y and z coordinates of the finger.
In this patent Apple also describes the possibility to have multiple controlling objects recognized by the sensors which is nice, but in my opinion again more an evolution than a real revolution.
Same goes for the idea of placing a scrollwheel on the display. Mouse gestures someone? IIRC you can already configure your PowerBook to recognize circular movements on the touchpad to do the scrolling. Sure, now a fancy GUI element pops up, but this shouldn't be all that hard to realize ;)
Now I'm just curious when Apple will release a device using this technology. All the diagrams look like they are for a tablet PC or an ultra mobile PC. Whatever it is, I trust Apple to let me know about it right in time, when I have no money ;)
But considering what I've seen of this patent I still have to wonder, what can be patented in the USA, because from what I remember of European Patent Law, you can't patent evolutions. Just revolutions :)