Petzl Nao is what I have for a backcountry trip next month. Pretty cool system that adapts to reflected light to save battery life. It is rechargeable or will accept batteries. I purchased a small solar panel to charge my headlamp, GPS, and camera should it need it. Beats packing a weeks worth of batteries around and then packing them out after they die. The set up isn't cheap but once you have it there is no need to ever pack batteries.