Otterbox
AT&T sells them. Also doubles as a weapon if
thrown.
Seriously though, I've had one on my phone since the day I bought it. I've dropped this thing off the back of a firetruck and its been all over the station and still kicking. Its a hard plastic shell with a rubber outtershell that fully incloses the phone from dust and damage. Little flaps cover the charger, headphone, and vibrate switch. Everything else is covered, including the screen.