You know that it is never Apple's spirit to add protectors or cases to the iPhone, since they always manage to reduce the thickness and give the iPhone the best screens. But what happens to the iPhone 5 proves that it is really not wise to leave it naked.
Here is a damage reprot from Gizmodo, take a look:
Below are two phones with very different lifestyles. One is a bit scratched up since launch day, one isn't. There's my phone, which was purchased on launch day, and has never known the touch of a case. I carry it in my pocket, or sometimes toss it in a bag with other stuff, every single day. The other (control) phone belongs to a coworker whose phone has been locked in a case from the day it was picked up at the end of September.
This is the iPhone with a case:
But without a case...
Yeah, there are scratches. Scratches deep enough to dig through the iPhone 5's matte black treatment and reveal the silver aluminum beneath. Compare the two phones above.