The only quality, compact, 100% waterproof box I've been able to find in the US is the Otter Box. They're good to 100', come in a variety of sizes and shapes and are available in yellow, clear, black and blue.
The most important way to maintain a fail-proof seal is to make sure the O-ring is clean. Especially free of sand. Even one grain. Also, if lubrication is necessary, make sure you lubricate it periodically with silicone grease, not water. You can find appropriate silicone grease at any shop that sells dive gear.