I've carried an Arc AAA light in a pocket with gobs of keys every day for many many years. It looks as good today as it did when I bought it - AMAZING. The only extra protection it has is I bought one of those plastic caps that go over the end of tubing and had to sand it down a bit to fit snugly over the LED end of the Arc. It stays on with no problem and removes any potential of LED damage.

Another light that I think is amazing, but consider it a tad too thick for pocket carry, is a Fenix single CR123A light - I don't think they make this specific model anymore. My wife carries one on her barn keychain, which has been tossed about in a pretty abusive way for years, and its still going amazingly strong - though it is pretty scratched up.

BTW, Arc's web site is http://www.arcflashlight.com