...Oh, as regarding what to carry, Ray Mears says he carries 3 types with him, a small LED keyring type (the photon microlight sort of thing), an LED head torch and a superbright halogen torch for emergencies.
Well this sounds very good to me. I figure a photon microlight on a lanyard, carried round your neck at all times is a good solution. The burntime is usually around 12 hours, which is pretty good, though the light output is paltry. It would double as a pretty effective "tent torch" when hung on a cord, though spare batteries (or spare photons) would probably be required for anything longer than a week.
An LED headlamp I would think is the "one" if you can only have one, it's the one to pick. A huge runtime, quite bright, comfortable, hands free, great for after dark walking, cooking, firelighting, firewood hunting, brewing up, kit shuffling, reading and whatever else you can think of. - something like the pricetontec aurora or petzel tikka+, fits the bill perfectly.
The emergency halogen is debatable. You might not need it at all, and if weight was a huge isse for you, you could probably comfortably leave it at home. But there may be occasions, when you just want the superbright, darkness-splitting beam for a few minutes. There are tons of options, most of them either thunking great2xD cell options, or lithium powered options. Lithiums are smaller, lighter, last longer, higher output, temperature tolerant and more expensive. Surefire lights are perfect, but again very expensive. The 5watt LED's are the first LED's which can truly compete with the halogen lights, but they are also much "whiter" than halogens, the bulb doesnt break and they last longer.
My choice:
1x PhotonII (on a neck cord)
1x Petzl Tikka+
1x Surefire LS4
All bases covered. The downside? The obvious one is cost - that's about £150 worth of torches, another is battery incompatibility. But as the LS4 is an emergency torch, I dont anticipate using or needing more than 1 set of batteries. The main torch is the LED headlamp - the only gripe, I would like a Tikka+ that ran on lithium AA batteries. Then I would sell the above and carry:
1x ARC AA (sinle LED to replace the photon)
1x Petzl Tikka (AA variety)
1x ARC L4 with AA battery pack.
...and about 1/2 dozen spare AA litiums for whatever torch ran out.
/end of ramble.