Funny. My Chinese friends think it's hilarious that Americans pay top dollar for the latest thin, light phones, then put them in bulky heavy cases. To me, the case protects and maybe more importantly, makes the phone easier to handle. But I can see their point.
That is why I have two cases, the Speck is very thin and still shows off the phone, which is fine for normal use. The Otterbox, which is a lot thinner than previous models I have used, is for when I travel, as I do tend to drop the phone from time to time as history as shown, and it's almost as bad to have cracked phone as a broken phone, to be without one when at an event.
Apparently Chinese must have superglue on their hands or don't worry about dropping the phone.
It all boils down to how you use it. If it was for personal use, I wouldn't worry so much, but since it has all my contacts, appointments, notes, etc on it, I tend to offer it a little better protection.
