I use just the rubber liner part of the Otterbox case. Couldn't live w/o it. I've dropped the phone countless times w no broken screens and it sticks to whatever you put it on. More than once, I've driven away w it on the roof or trunk of my car, figured it out miles later and it's still there!
The only warning, and it's a big one; twice in recent years I've accidentally pulled a folded over envelope full of hundreds out w the sticky phone from my pocket and lost the $$ forever. Once it was *trip to Europe* type money and the other time it was about a grand.
Can't believe I'm admitting this here.