I put one of these on mine. It’s far from perfect, but there are now no visible scratches on my nano. When I wiped off the device with the microfiber cloth I use for my glasses before the film application, it did actually leave streaks in the direction I wiped that I could not get off by rubbing at a 90 degree angle (although with minimal pressure) so the scracting with a microfiber cloth stories are true. I probably wouldn’t have seen the scratches at all if I had a white one and the texture of the film hides it so you’d never notice.
I did get a kick out of this comment, though:
It’s true! Not only are nanos susceptible to being shoved in a coin & key filled pocket and sat on, but aluminum PowerBooks are susceptible to damage from nails that are pounded clear through the case, and I have noticed that Apple’s install DVDs are much more flammable than their competitors’. For shame.