Actually, to use the quoted example: If you were reading Spiderman, and it started with a nerdy kid getting left behind by the bus, what would make you interested in that nerdy kid?
It says "Spiderman" on the cover, so you know that this is probably the kid who is going to be spiderman, or someone spiderman is about to rescue, or perhaps he is to be the antagonist. Either way, you know he is more than an ordinary nerdy kid.
You don't have to start your novel with a car chase or battle or some such action scene. If you do, you are promising the reader a novel full of action action action and nothing but action, and if you don't keep up this pace, you will disappoint your reader.
Look at the beginning of
Storm Front. Harry is in a very ordinary situation: receiving mail. BUT something is not quite ordinary about this: a) it's probably bad news, b) the mailman asks if Harry is serious about his sign saying wizard. When long ago I discovered this novel (no recommendation, I was just browsing first pages at amazon to find something to read) I was immediately hooked. A good beginning (first chapter) must set the pace, the tone (
Storm Front is funny right from the beginning but Harry sounds also a bit desperate), the scene (Chicago, office of a wizard P.I), introduce the main character and a few supporting characters, but not too many, and get the plot on the road.
It's probably better not to compare book openings with movie openings, because in the movie much relies on the main actor's charisma. Luke Skywalker and Toby Maguire, they are both kind of cute. In a novel, you can try to describe your character as handsome and charismatic, but the reader won't believe it until he sees the character in action, sees other characters around him admire him, hears him say witty things, or do heroic or helpful things, make decisions either right or wrong, etc.
Like AverageGuy said, Luke starts out
wanting something. The audience immediately wonders if he will achieve what he wants, and anticipates -- since we already know about the intergalactic struggle -- that Luke will probably get a lot more excitement than he is hoping for a lot faster than he suspects.