The Griffin Survivor case for the iPad 2 follows in the footsteps of the similar case for the iPhone 4, which combines a shatter-resistant polycarbonate frame with a thick, shock-absorbing silicone shell. An integrated screen protector keeps your vulnerable display safe, while hinged plug-covers keep out moisture and debris.
The Griffin Survivor was designed to meet U.S. Department of Defense standards. More specifically: the screen protector can withstand wind and rain (200mm for 1 hour), the device can be dropped from a height of 6 feet (1.8m), the ports resist sand and dust (18m/sec for 1 hour), and the device can endure vibration at 80 to 2000Hz for 18 hours.
Not that your decision will hinge on this, but there is also a flipout stand that functions in both portrait and landscape modes. For US$79.99, its' a relatively expensive case. But considering your overall investment (financial and emotional), it's well worth it.
source: Griffin via Pocket-lint