Fire Piston

[Paul]

One word, Ferrocerium.
aka Firesteel, Blastmatch, and Metal-Match.
Works everywhere, usually everytime, and lasts a long, long time.
No moving parts and cheap (£3 upwards).

You'll need char cloth or amadou fungus for tinder in a fire piston.
It's got moving parts, and it doesn't like getting wet.

IMO always K.I.S.S. (Keep it stupidly simple).