I'd recommend a Zebralight one (I like the H600Fc), as they're small, light, and much brighter than most headlamps you'll find. I've also had good luck with Ar

I'd recommend a Zebralight one (I like the H600Fc), as they're small, light, and much brighter than most headlamps you'll find. I've also had good luck with Armytek (Wizard Pro Nichia), though people say their reliability is lower.