I just picked up a Petzl light (I got the Mega belt, so I can stick the pack in my coat ** )and am really impressed with it. I believe that most of the lights work of the same bulb, and are mostly 4.5 volt. I am _very_ impressed. No light, no moon illum, clouds and snowing. The only downfall was lighting up the snowflakes in front of my face. It lit up my trail nicely, with more light than I needed and to a greater distance than I was paying attention to. If I do any casual skiing/hiking, I'll give you a better description.
I've long been a fan of maglights, and have seen them used to pound in tent-stakes on a regular basis with no ill effect. (Not I, there were more foolish staffers than I that I worked with though...). I have no use for a diving light, and do not expect me to survive long at 30m underwater, though I have used a maglight at depths to which I can survive, and reach easily (<5m). Once, I got minor condensation on the inside. That was the worst. I really like 'em. Yes, the aluminum is nasty in the cold, but if it's that cold, what're you doing without gloves to start with? I have cold-soaked a 3D maglight before, and I'd not had experience with that before, and was ticked that my second bulb had burnt out too...
But that is the result of storing my light in the snow-hole I used to point it, rather than in my bag with me...
There are other lights out there, brighter, lighter, and more expensive. But the brighter ones eat batteries faster, the lighter ones will not survive pounding a tent stake in, and the more expensive ones, are, well... more expensive. There are trade-offs for everything, and for a multi-use flashlight, especially one I can stick on my belt, and keep there, I like the maglight...
Stryver