For a long time, I felt guilty about this, as if it somehow it indicated I was less serious than other runners. But more and more, I have been seeing articles like this one in the New York Times. The bottom line? There really isn't much evidence that static stretches--the kind we learned in high school--are useful in any way.
Of course, these things are notoriously difficult to study scientifically. How in the world can you set up a study where two groups of runners are exactly equal in all respects, except that one has stretched and the other has not? At the end of the day, we all individually have to keep experimenting to figure out what works for us (and what we enjoy).
Do you stretch before running? If so, how do you think it benefits you?