I'm not a typical gear-hound, but travelling recently, I bought a copy of Popular Mechanics, and they had a list of very tough flashlights. These flashlights were used to pound 12 iron tent stakes into the ground, run over with a 1973 MGB, submerged in water for 7 hours, and dropped on concrete from a height of 25 feet. And they all survived.
Yes, they are expensive, and as the article points out, there is a perverse pleasure in using a $300 flashlight as a hammer. But all of these flashlights survived to live another day.
If you are in the market for a tough flashlight, you couldn't get better than one of these.