Warning - iPhone4 glass breaks easily
Checking around, the glass is not as durable as Apple would have you think. There are lots of shattered iPhones and it's only a month old. I have their bumper too to protect it so it isn't like I haven't taken precautions.
So what's with designing a cell phone out of glass? Two sheets of relatively thin glass. Seeing how easy it shattered I think this is a poor design. Certainly not one I can recommend.
iphone 4, iOS 4