An Editor's Choice Gold Award winner last year (4/08), the Lithium's recipe–minimalist design, excellent fit, 850-plus-fill down–makes it a perennial go-to bag for cold-weather trips when weight and warmth are equally important. A thick draft collar and zipper tubes seal in heat, and a contoured hood secures without scratchy Velcro. It stuffs magic-trick small (football-size) for a true 0°F bag, yet puffs up quickly even after being crammed in a stuffsack for days.
The shell material is filmy light, but testers failed to tear it in a year of use, and the DWR-boosted water resistance is just enough to keep dew at bay. The down is distributed 50-50 top/bottom, so it's warm for side sleepers. $459; 2 lbs. 12 oz.; 0°F