Well I just ordered the North Face Furnace 35 degree down bag, that I found on sale. I know its not the lightest bag, but at 2 lbs its a good deal lighter than my synthetic Marmot 15 degree bag. I think it should be a good bag for most summer camping, and if I know its going to be colder I'll just have to suck it up and take take my old heavy warmer bag instead.