My three favorites are Wetfire, UCO Sweetfire matches, and a standard road flare. Wetfire is a trioxane-like fuel, but comes in individually packaged, lightweight cubes. Like the name suggests, it ignites easily when wet, and burns for several minutes. The Sweetfire matches are super convenient, as they combine ignition and fuel in a foul-weather resisting match. You do need to protect them somewhat, as the ignition coating can flake off, but they are fast and convenient. Finally, a road flare is one of my favorite emergency fire starters. They are cheap, and they ignite and burn hot in just about any condition. It essentially gives you a blowtorch to start your fire, and even a cut-down flare burns long enough to get damp wood to burn.