What is the best combination of items, so that one can absolutely, positively spark flame in a controlled manner when needed? This should probably include tinder materials as well.
I'm not convinced that this is the "best" combination of items, but the last time I updated our emergency kits I built what I called the "Fire Now!" module for each of them.
- Mini Bic in a "ranger bic" keyring holder (https://gearward.com/products/ranger-bic), inserted upside down for waterproofing and button-protection
- UCO Stormproof matches with striker
- UST Strike Force
- UST Micro Spark Wheel with extra flints
- Tinder-Quik
- Tinder Cards
- Esbit fuel tablets
I've been successful starting Tinder-Quik with every kind of spark-producer I've ever tried. The Tinder Cards are harder to light but seem to burn longer and hotter, potentially bridging the gap between tinder and kindling.
This packs down to a small size in a quart freezer bag. If I can't get a fire going with that stuff I've probably got bigger problems.