Canon PowerShot D20 Digital Camera Review$349.99
If we trust Canon's durability ratings (and there's no reason not to), the Canon D20 isn't the most overall rugged camera on the market, but it's competitive with the most tank-like compacts out there.
It's waterproof to 33 feet. The deepest diver in the class can survive in 40 feet of water, but 33 isn't bad. It is not designed to survive in hot water, like hot springs, and the camera needs to be cleaned after dips into salt water. And according to the manual, "waterproof performance is not ensured if the camera is dropped or subjected to impact." Canon advertises it as a shockproof camera (see below), but that confidence only extends so far, apparently.
It's shockproof to 5 feet. The hardiest camera can fall from 6.6 feet—over most people's heads. But the D20 can still live through a tumble from chest- or shoulder-height. Like we said above, Canon doesn't ensure the waterproofing if the D20 "is dropped or subjected to impact," so it's not a good idea to drop the camera for the sake of testing its durability.
It's freezeproof to 14 degrees Fahrenheit. Just about every tough-cam shares this rating. It basically means you can take it skiing.
And finally, it's dustproof. All the moving parts are protected by glass, plastic, or rubber, so the lens won't get jammed up by an errant grain of sand.
For most people, the D20 is durable enough for general underwater and outdoor use. Take it to the beach, the pool, the slopes, the state park, whatever. But serious divers will be better-off buying underwater housing for a more capable camera—it'll survive deeper underwater, and take better pictures, too.