Other people on the web seem to have noticed the scratching issue on the new iPod nano, although as usual it seems a little hysterical. I especially like the person claiming that the screen is 'illegible' and yells about class-action lawsuits and then includes a photo in his post that only shows the click-wheel part of the device under strong light. Hmmm.
The first day that I took it out, it acquired a long narrow mark - that looked like a crack but wasn't - along the left side, which was really sad, since the device came out of the box as this perfect tiny smooth thing, like the monolith from 2001 turned into jewelry. After a week or so it has acquired a few other scratches, as well as some abrasions that distort a part of the extremely high-pitch colour screen a little bit - white looks a bit like tiny bands of colour.
Then I took a look at my previous iPod (white with the row of buttons on the top) and realized that it was really thoroughly scratched up too, far worse than the nano - but I hadn't even particularly noticed.
A tiny black shiny device is going to show the same scratch much more than a larger white device. Also, the simple black and white screen has huge scratches over it, but they don't impact the viewing experience that much, since it has a low resolution and no colour. The nano screen is very small but very sharp and in colour, which, as I noted above, can cause a rainbow effect with distortion.
I think the main issue is that Apple kept the same manufacturing materials and process, but made a much smaller device, which makes it easier to notice the problems that have been there all the time.
One of the posts on Slashdot noted that while polycarbonate is extremely durable, it does tend to scratch rather easily. I'd rather have a scratched nano than a broken one, considering how much trouble such a small object is likely to get into. It would be nice if they added an extra coating to it or something.
You want to see scratches? You should check out my Canon digital Elph camera! I like to stick it in my coat pocket when I walk around, and once it got accidentally thrown into a bag with my cell phone - a layer of black coating on the back screen was almost entirely rubbed off and it now has wear marks along most of the corners. My own fault for not getting a case for it, really. The cell phone, though, seems to have mostly survived.