Here's the thing about firemaking under survival conditions: You need fire the most when it is the hardest to make. Like when your fingers are numb from hypothermia or its been pouring down rain for days. My number one pick for starting fires in a survival situation is a spark-rodalso called Swedish steel, a metal-match, or a zirconium rod. Unlike a lighter, a spark-rod has no working parts and will even work when wet. (It works by rubbing metal across the rod to create sparks.) Even better, with some practice, you can use it with just one hand.
I also carry REI StormProof Matches, which are reminiscent of those trick birthday candles that probably foiled you as a kid. They'll stay lit in a fierce wind and will even continue to burn after being submerged in water.
Half the challenge of starting a fire is in having the right tool and being proficient with it. The other half is in having the proper tinder, the best of which can be made. Coat a few cottonballs with Vaseline and then place them in a small Ziploc bag in your daypack. One petroleum-soaked cottonball alone will burn for around five minutes.
Whatever tool you decide to carry, make sure you've tested it out before you actually need to use it under survival conditions. Since many real-life survival situations involve people who are hypothermic, injured, or both, being able to create firewhen you really need itcan be the best life insurance policy you can take when you venture into wild places.