I think WM makes the best down bags, and a 15 deg. bag would be pretty versatile. I'm a big chicken, but I generally do not use a down bag in the Cascades. I've been in a 7 day storm where everything starts to get wet, and I never had to stress about my bag, whereas my partner did, as his down bag started to get lumpy and cold. Also, a synthetic bag may be a little more versatile than a down bag in a rescue situation (God forbid). In other places, like the Tetons or the Wind Rivers, I use down.