For ANYONE concerned about the durability of the iPod Nano, visit this website:
http://arstechnica.com/reviews/hardware/nano.ars/3
The iPod Nano was tested in the following ways:
1) Sat on (wooden chair)
2) Dropped from a car from 10, 20, 30, and 50mph
3) Dropped from 9 ft
4) Ran over at 10mph
5) Thrown up 40ft in the air and landing on concrete (this is the point at which the iPod actually stopped playing music)
The website features pictures as well.