I live in an urban environment, for me its gotta be the following:
1)knife-currently a Vic Swisschamp
2)fire-zippo
3)light-nitecore infinity
Even in a rual or wilderness setting I'd have these, maybe swapping the swisschamp for a swisstool (locking blades) and switching to a 2 cell AA LED light (vic rebranded inova IIRC)

I'd have to say Knife, FireSteel, Flashlight

Starting with these three items, you can just about conquer the world.