Now if we all agree hooking the reader is important, how do you do it?
A lot of writing instructors will suggest that you start the story in the middle of THE ACTION. You know, "Twang! The arrow barely missed her head," and such like. That method can be effective, and it's a good thing to try particularly if you feel like your story lacks a certain amount of movement or if you've been having trouble with your pacing.
Not every story needs to start with a literal bang, however.
In science fiction and fantasy, you can also start with an eyeball kick, as William Gibson did in his famous opening for Neuromancer: "The sky was the color of a television set tuned to a dead channel."
Juxtapositions work well too. I'm not sure I can find the exact opening, but Mike Resnick's "Scherzo with Tyrannosaurus" would be a good example of how putting to disparate elements together can grab a reader's attention. Turns out it was downstairs. Here's how it goes: "A keyboardist was playing a selection of Scarlatti's harpsichord sonatas, brief pieces one to three minutes long, very complex and refined, while the Hadrosaurus herd streamed by the window."
From the same collection, this alternative from "Mount Olympus" by Ben Bova, "Tomas Rodriguez looked happy as a puppy with an old sock to chew on as he and Fuchida got into their hard suits." What I like about Bova's is that nothing is really happening. It's the turn of phrase that sounds very American South coupled with a term I'm not sure of "hard suits" (space suits? something else?) that catches and holds my attention.
Let's see if there's anything else fun in here (BTW, I'm perusing the SEVENTEENTH ANNUAL YEAR’S BEST SCIENCE FICTION, edited by Gardner Dozois). Okay, here's the beginning of Paul J. McAuley's, "How We Lost the Moon, A True Story by Frank W. Allen"--"You probably think you know everything about it." A provocative accusation in second-person (you) which jumps out and bites you, personally. This works for me, especially given the title of the story. Something like that could work for you, too, perhaps.
One thing that writing instructors will also tell you, but which I've actually found fairly useful, is that sometimes it's best to leave the beginning to the end. Which is to say, start the story wherever you need to in order to write it all the way to the end, and then, once all is said and typed, go back and revamp your hook so that it's catchier. Also, depending on how you write, you may not know what a story is about until it's over, and really, the beginning paragraph of a short story (or first chapter of the novel) should lay out the main conflict of the main character. It needs to answer the question: What’s at stake here? Who stands to lose the most?