A headlamp haiku: Went out to climb ice. You stayed in canyon past dark. Now you are screwed. Wait, is screwed one syllable or two? Oh nevermind. The whole point would be moot if you had brought a headlamp.
I was in this situation last week, and lucky for me I had the Petzl Myobelt SB5 headlamp in my pack. That allowed my partner and I to get on a popular climb after dark that had been busy all day.
Headlamps are difficult to distinguish these days, there are so many good ones out there. What makes the SB5 a standout is the hybrid combination of focusable Xenon halogen/five LED bulbs and the remote battery pack. The remote is a big deal in cold temperatures, as keeping the batteries next to your body greatly increases their life.
There’s another big advantage to the remote, and that is the reduced weight on your noggin: only 3.7oz. I use it with the Petzl Meteor III helmet, only 8.2oz itself, for a combined head weight of about 12oz. The LEDs are fabulously white and bright. The halogen is the only ho-hum part of the package, as it casts a slightly dim spot. If you need a lamp for mostly long-range work, look elsewhere. All others will be mightily pleased.