I have to second the completely unbreakable part. I have dropped it whilst biking many times (seriously I'm embarrassed to say like 4 times) and it has only a few minor dings to show for it despite tumbling on asphalt at 10-15 mph. It seems like the thickness of the aluminum bezel coupled with the thinner screen width protects the screen better than the ipod touch's. I also prefer the UI and basically what it came down to when deciding between the two for me was what I wanted: a really good touchsceen mp3 player or a more generally useful device/portable gaming machine. I already have my phone for the latter purpose so I went with the best mp3 player.
I did have mine "break" but I can still use it. Somehow the screen cracked from the inside. Speculation is the battery was overcharged and swelled. I looked it up on the Internet and pretty much every discussion about it was filled with people claiming those with broken screens must be lying or had damaged it somehow. Microsoft doesn't acknowledge a problem.
Oh well. It still works, and I have my WP7 now. The Zune is just for biking.
