I dont use a case for a number of reasons:
1. I bought a case (leather folding) and it vignetted the camera, and pretty much doubled the width of the phone and weight.
2. The iphone is gorgeous design, industrial glass and metal. I dont want to hide it away. It's like folk that put throw sheets on their expensive couches, or poly covers on their car seats 'to keep it new looking' Damn. So new looking you cant even see it.
3. A case would prevent it from fitting in my car holder, and without a case it fits nicely into my trouser/jean front pocket. Cases are too kludgy.
As for dropping it - I've dropped it numerous times from a height of a couple of feet, e.g. off the edge of the bath, of from my lap to the floor when I forget it's on me and I stand up.
The other day an unfortunate set of circumstance led me to dropping it on tarmac and it chiped a bit out the edge of the glass beside the mute switch and a scratch on the antenna further down. I put it in my shirt pocket (which I usually never do) and shortly after bent down to look under my car (which I don't normally do) and it just slid out onto the ground.
My screens has some small scratch on it as a result of use, and so does the rear. Who cares? Not me.
And finally, the iphone is super smooth, I find resting it on things it majorly risky as it slides on just about any surface unless it's totally level. Even holding it vertically between fingers is diffilcult sometimes. You need Gecko fingers, seriously.
I would use a case if:
I could keep it on and fit it in my car holder,
it didn't bulk up the size/weight of it, so far I haven't found a suitable case.
Edit to add I just remembered the funniest thing - I was waiting in traffic and somebody was fiddling with their iphone as they cross the road, and had headphones hooked up as well. I don't know how it happened but he totally got messed up and the iphone went up and he kind of juggled it for what seemed like forever before finally losing it and smashing onto the ground and bouncing. His face was priceless!.
