This is the best light I've found so far for controlled use while stumbling around in the rocks
http://www.inovalight.com/x.html
I use the small single LCD X1 on a piece of old fly line around my neck. About 25 bucks. Light enough to carry a spare. Don't need to worry about battery usage. Seems pretty waterproof. Broke one that they replaced no hassle. Used head lamps for years but find this much better.