I'm with Hampstead, and have begun to carry a firestarter on my neck knife lanyard occasionally when I'm bowhunting.
Those tear-open chemical packs are fantastic, and light. A really nice feature is the ability to shut them off for later use by sticking them into a Ziploc bag. I'm not a big treestand guy, but I can stay in one all day in subzero temps and wind with the use of them. I even found a velcro pouch belt in a drugstore that places a large pack over each kidney...unbelievably effective.
