When selecting a headlight make sure it can use lithium batteries. They last longer, do better in cold weather, weight less, and DON'T LEAK!

Well except for my backup lite (Petzl E+lite), I use them frequently enough to run pretty much NiMH all the time. Won't leak either, more frugal in the long term and pretty good performance.

Just avoid alkaline batteries like the plague! I put primary lithium bats in lights used only intermittently, and my "work lights" use rechargeables. Things work a lot better that way....

I find rechargeables undependable. They don't always function in high drain applications and older cameras, GPS etc. Lithiums run out without warning. I bring backups of alkaline by the batch for extended trips and use the free Harbor Freight heavy duty batteries for everyday use in the devices the rechargeables won't function.

Presumably we are talking about AA and AAA batteries, which makes us pretty much dinosaurs in terms of cutting edge battery technology. Lithium ion batteries, 18650, 14500, and the like, offer some real advantages in terms of capacity and reliability. They also offer snares for the unwary,so one must learn a bit, take precautions, and follow good practices.

I have a Zebralight headlamp that uses 18650s and it is the best headlamp I have ever used, and I will probably acquire more in the future.

One aspect of rechargeables, either NiMH or lithium ion, is their cheaper cost over the lifetime of the batteries. This is rather significant, because I find that a lot of my "precious" run on batteries, and more are on the way.

I also own a solar panel, and have the ability to charge my smaller batteries with nothing but the sun. That could be handy sometime.

I also recommend reflective gear (hat, belt, pack) -- makes it easier to be found

I am adding a spare, external cell phone batterey

Matches and lighters - I recommend buying a 5 pack of Bics for a camping trip.
(Non smokers always forget)

Sorry for the delay in getting back to defend my idea. While you have a good point, I find that a .99 cent toothbrush case is the perfect vehicle to store them in. It seems to protect them well, and does not add significant weight. I usually carry 3 or 4 in a midsized kit without problem.

Given their ability to put out light for a good 8 hours and longer, coupled with the idea that swinging one around on a string is a great attractor beacon, I would submit they are certainly worthy of consideration.

Yes - and my energizer glowstick with a handful of batteries can go 100+ hours...