All these lists focus on our beloved gadgets. A condom/canteen holds water. Why is there so little thought to our own reservoir of body heat? There are first layer systems for every circumstance; polys, silk,smart wool and fishnet. A watchcap and mittens greatly increase retained core heat. A poncho AND liner, while not always the best raingear, are doubly versatile as an expediant shelter and insulated groundcloth. Bandannas !!!!!! None of these items take any great space or draw curious looks. Long sleeved shirts can always be rolled up in warm weather. Try rolling down a short sleeved shirt after nightfall !