Shades Case/Cover for iPod nano 5G (5th Generation) w/ camera (8, 16GB) - Serene Green
This case is awesome.  It is small and tight and keeps the iPod looking like an iPod.  Color is extremely vibrant and funky.  I love that you can change the color of your iPod at such an affordable price.  It also allows you to easily use all the functionality of the iPod without taking off the case.