This Black Diamond Astro 175 headlamp offers excellent value in a compact unit that weighs only 81g. It takes 3 x AAA batteries (batteries are included) and has dimming and strobe functions. You'll appreciate the brightest light for cooking, following trails and looking for stuff, and the dimmest beam for reading. Burn time is up to 8hrs on the brightest output (22h on medium and up to 200h on low).
This headlamp is splash proof, not waterproof, so drybag it when you're on the water.