To keep this as simple as possible, the bare minimum knife I would grab would be a Mora (I have several different models and any would do). A mora style knife does everything any knife should do, and does so with flying colors. Will it split logs into firewood like one of those sharpend prybars some people like? No, and its a lousy hammer, wrench, corkscrew, cooking pot..etc. Its simply a great knife, for knife work.
In reallity unless I was fleeing naked, there would also be a folder in my pocket, and a CS bushman in my pack.
So, folder, mora, and bushman are the basic "knives" I would take, but the last thing I would do is focus on "the knife"...the knife is not the star of the show.