I was looking for a waterproof case for holding small electronic devices, such as a mobile phone, PDA or MP3 player. There a wide range of units available, ranging from what is essentially a thick plastic bag, though to small hard equipment case. Some of these are designed for a specific model of phone or player (with many for iPods). Some cases are designed to fit a rage on models. Some have a hard shell, combined with soft plastic transparent windows to allow the display to be seen, buttons to be pressed and sound to be heard through the case.
The most rugged general purpose case I have found details of is the Otterbox 8000. This is about 1.8 x 2.8 x 5 inches on the inside. It has a belt clip and loop for a strap. They are about $US21 from Amazon.com. However, I would like to see one before buying it but can't find a supplier in Canberra. Anyone know of one?
There is also the 50 Series Universal Hardcase from Tactical Tailor. This has two belt clips and a dust/water resistant seal. These are slightly smaller (2.5 x 1.25 x 4 inches inside) and cheaper ($US19.50). TT also have a larger Series 75 Universal Hardcase. These appear hard to get in Australia. Also given that TT's products are mostly for the military, ordering one of these might bring you to the attention of the authorities. ;-)
Like the Otterbox, the TT hardcase is a hard shell designed to protect the elelctronic device. You have to remove the device from the case to use it. But this makes the box general purpose.