This week seems to be turning into a bit of a writing-tip-a-day festival. Continuing this impromptu thread is this Writers Digest article from a few weeks ago.
Think of every opening line you write as a pebble tossed down a mountainside: The stone may jolt back and forth within a limited path, building up force, but the trajectory of its initial release largely determines its subsequent route.
It's a thorough article, and although I generally am averse to 'x ways to y' style articles, sometimes you have to look past your prejudices.
Sometimes a story evolves so significantly during the writing process that an opening line, no matter how brilliant, no longer applies to the story that follows.