Another thing for the cold weather is a down air pad, Exped makes an awesome pad, expensive, light weight,built in pump,very compact, durable and very warm. If you have a good down bag like a Western Mountaineering or Feathered Friends and a good down air pad like exped, you can be really comfortable when the temps pull down. I'm currently visiting up in the smoky mountain area right now with temps dropping down to 14 degrees here and everything you can do to limit heat loss definitely makes life bearable.

I've tried a colman propane heater in the tent but at low temps, it was useless. I only had one of the hand held ones, I know Northern tools sells bigger ones that may work, but then you get into serious Carbon Dioxide Poison if you are not careful. I can't remember what we used in the military but we rented a big propane burner from special services and used it in a 10 man tent and it was -5 F outside and 90F inside but it was big and bulky and consumed a lot of fuel.



http://www.rei.com/product/780366



http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200332707_200332707