My Nano screen scratched on the 3rd day I had it. Sort of a foggy brillo pad scratch that almost looks like it could be cleaned off but doesn't. Since then I have been carrying it around in an Oakley sunglasses microfiber sleeve, but I've read that someone used microfiber cloth to try and clean the screen and that scratched it.
Such an achilles heel has really tarnished the iPod image. If it cost $49.95 none of us would be complaining but at $250 they could put something harder, or have provided a case instead of making us wait to buy 5 cases, 4 of which we will probably never use. Here's an idea for a killer website, a way to pass your unused covers on to other users. It's like a Nano dating site where you match up Nano's with unused covers!