I managed to crack the screen on my iPod Nano - forgot it was in a bag that ended up at the bottom of a big heavy pile of things. It seems that the screens are the weak point - the plastic and metal body didn't have any dents or warping at all, but the LCD had cracked all the way across, and black crystal (or whatever it is) had oozed out over the left side. It also seemed to stutter briefly about every 20 minutes or so, which probably meant something funny with the RAM.
After a few weeks of trying to navigate around my playlists using only the top right corner of the display, I took it to the Apple Store at the Eaton Centre. It was around lunch hour so I had to wait for a little while. There's not actually that much to look at in an Apple Store - especially if you're up on what Apple is doing and you use their machines already - so I sat at the Genius Bar and watched all the people, which is much more interesting.
When my name came up, they looked at it and just gave me a new one - no questions asked! This close to the end of the warranty, they do charge a $55 'stocking' fee - or I could instead buy the extended warranty for about $75, which is what I did, so my new Nano is covered for another year.
This is a different approach to warrany replacements - my previous experience with these kinds of things at other stores is that they haggle with you and try to make it your fault so they don't have to replace anything. This way, they give you a brand new one immediately, and then ask for a bit of extra money. Psychologically very different.
When I got the Nano last September, there weren't any cases for it available for several months, so the thing got rather scratched. The replacement has gone directly into my black inCase nano wallet - I only take it out every so often to admire the smooth clean tiny-2001-monolith finish of the thing - then it goes right back.