The main character in Snow Crash is not the most interesting, but that's not a bad thing. His name is Hiro Protagonist, which should give you a clue as to his purpose in the story. He's the one that works out the plot, is in the right place to save the girl at the right time and saves the day by being the badass every geek wants to be. He does this job really well. It's the supporting cast that really lift the book, though: Y.T. the skateboarding courier that hides her job from her mom; Uncle Enzo, the vietnam vet that's head of the mafia (who also deliver pizzas); Raven, the unstoppable baddie.
This is a great book, a classic of S.F. You should read it.