Well, the first chapter doesn't make or break the story. It does, however, make or break readers' impressions of the story. If you have a great story with a horrid first chapter, it doesn't make the story horrible, but it does make everybody press the back button at soonest opportunity (or, alternatively, tell you to get your butt over to Advice for Aspiring Authors before attempting to write).
In the long run, a bad first chapter generally doesn't affect the story nearly as much as, say, a bad last chapter. Actually, now that I think about it, the last chapter does make or break the story. If you have a great fic but don't get the last chapter right, it can ruin the whole thing. I don't think the first chapter will ever do that. It just scares readers away.