From an adventurer's point of view, going north has this dramatic flair to it, ya know? /raijin

I mean, when someone is going on an adventure north, it makes you picture that they're going on this brutal, difficult trek up the Earth, and once they get there, they're basically on the top of the world. Likewise for important locations being on the ends of the world map. It creates the feeling that it's a grand-scale adventure that will take them to the ends of the Earth -- literally!

Also, using "Northern" as an adjective sounds cool. "Northern Lights", "North Winds", "North Pole"... Using "South" just makes me think of rednecks.