Yes - went naked today.
Had a black iPhone 5 that had a case on it pretty much since launch day. I gave it to my wife and got a white iphone 5 and wouldnt even think of putting a case on it. It's just too damn sexy without a case.
I do have Applecare+, so it does give me a sense of security...much like a case does
If I had Apple Care + I'd never ever use a case.