For sub zero temperatures at camp I will either wear an Alpkit Down Jacket or a Snugpak Sleeka Reversible Jacket and trousers (Similar technology to the Snugpak Softie Special Forces sleeping bags).
Not to steal the thread, but how do you like the Snugpack stuff? I've seen some of the sleeping bags and parkas in various catalogs, and wondered about them. Haven't heard much about them (good or bad) in the US.