I think the shooting inspired a number of good books and docs that delved into issues that are very important from a cultural and political point of view. The role of violence in American culture and the cost of fear. While I don't subscribe to the idea that media causes violence or bad behavior, it is always good to have an open, public dialogue about the kind of media we surround ourselves with everyday.
The shooting also challenges anyone who hears about it to question what it means to be a parent. What are parents responsible for, exactly and what, exactly, makes a "good" parent? And is "good" parenting enough to stave off a violent event like NBK?
A similar case can be made about the responsibility of official agencies across the board, all of which failed in the case of Columbine. That's the real shame of all the CYA behavior that has obfuscated evidence and enabled a skewed perception of the boys motive to be launched against the public. But these agencies are shamefully exposed for anyone who cares to look closely enough. So how much can we trust those we pay with out tax dollars to protect ourselves and our kids? And can we expect them to own up to it when they fail?