I use a North Face Blue Igloo 20 degree down bag. I also carry a cool max mummy liner, and many nights, just pull the bag over me when I get cold. That way, I have sleeping gear that will take me from hot and humid (minnesota) to freezing cold (minnesota). I don't worry about getting the bag wet, it is somewhat moisture resistant (it's got pertex on the outside), so I survived a night in colorado after I got hit by some sprinklers in it.