I would be interested to know if the shake feature is something you can turn off. Otherwise what happens when you jog (or dance like those silhouettes in the ads...hehe).
I would also be interested to read about how many people accidently throw their nanos out of their hands (like the wii-mote).
I wish Apple would allow you to turn off the accelerometer in the iPhone and iPod touch. It annoys me to no end.