I am a phone fanatic and upgrade around every 6 months I currently have an iPhone 5s and I will probably be keeping it a while. I agree with previous statements that life proof makes a great case I've used one on all my iPhones so far. But with the 5s I use the sleeve for the iPhone made by saddleback and I absolutely love it. I don't have to carry a bulky case and it protects it from scratches and bumps. (I do have a screen protector on it though.)
So apple's marketing plan actually does work on some people??? :O
The more ya know.
I personally use a g-form case. Has saved my phone from multiple high impact falls, even from a 20' deck that I had been working on. Case is a little scratched up but phone has taken 0 damage. I'm also a little biased because I have a skateboarding sponsorship through g-form though.