If you go to the CPF forums, you can read a tremendous amount about headlamps in the dedicated subforum--which, by the way, is filled with hikers, cavers, and bicyclers. If I were to guess at the most commonly recommended headlamp for backpacking by the CPF'ers, it would be the ZebraLight H52F, because that beam is a center-weighted flood, so does duty both for night hiking and for trail chores. It's small, efficient, and hardy. If it were me, I'd avoid the cool white version.
The light is so efficient, there's no need to turn it off at night. Just turn to one of the sublumen modes, and set it in the corner of your tent, or clip it to a guy line, so you can easily find it when you need it. The light will run continuously for 2-3 months in the lower sublumen modes from a single AA battery.
Weight of the light is 32 grams / 1 oz. On high (depending on model) it can blind you with as much as 300 lumens.