Down filling is the lightest, warmest insulation around. But it fails when wet, making many mountain-goers turn to winter jackets stuffed with synthetic insulation. This 800-fill Brooks-Range Mountaineering Mojave employs a coated down that's water-resistant, ensuring continuous warmth when soggy. Outside, it's equally impressive: Its light fabric breathed well even on the hardest days of downhill. [$300;]