I've had nothing more than a protector on the rear and front since new on my iPhone 5. 12 months in, and still looks as good as new.
I would like the 5S, it's not a huge step up but excited to see how the 64bit CPU is utilised.
More than anything, I desperately want Apple to create a phone with a 4.8" screen. Looks like we have to wait for 2014 for that.