In reply to Boulderdash86: I use the BD Icon - very powerful and the time of buying, felt it was better than the Petzl Myo XP (this was all before the new Nao and reactive lighting, so I'm not sure how they compare).
I've not had a good run with the LED Lenser H7 - found the light output diminishes radiply (unlike the BD and Petzl which, by funky electronics, seem to maintain a near constant light output, regardless of battery age, then die), and also the rachet to adjust beam height wears down quickly/is loose, so any jolt when walking, etc and you have the beam in your face, as opposed to where you want to be going.