Three Points of the Compass believes that at least three methods of starting a fire should be carried on trail, certainly on longer hikes. This should definitely be the case for a solo hiker who cannot scrounge a light from a fellow hiker. Matches make an ideal cheap and lightweight final back-up and I wrote a little on these previously. A Bic lighter remains the favourite source of ignition for many, and for those, an 11g Mini-Bic is the preferred type as they are cheap, light and long-lasting. I carry one myself, though that is stored elsewhere in my kit as a back-up (that said, a 20g Torjet is a far more efficient lighter). Before all of these, my favoured method of lighting a stove on trail is a small ferrocerium rod, more commonly known as a ferro rod, less commonly (and incorrectly) called a flint and steel.