Old Hex 3 (now Shangri-La 3) in all seasons, with water-resistant bivvy alone in hot weather. In cooler weather, I add a sleeping bag.

If I'm alone and want to cut weight, a SilShelter instead of Hex.

My bag collection consists of a very raggedy (very compact but only marginally light) duck down and feathers job that is good to 50 degrees, a super high-priced 40-degree job, a very old, well-cared for REI bag with (originally 2.5 pounds of down fill) and a NF synthetic once rated at twenty below, but now of dubious value and not used.