Now that Buffy is over, we can reflect on the entire beautiful run, and realize that while the show may have ended, it has changed our culture, and through that (and reruns) it will continue to live on.
The series may be done, but the influences left on television culture are unmistakable. Without a demon-kicking Buffy the chances are there would be no Sydney Bristow on Alias, or Charmed witches, and series pitches for Smallville and Dark Angel would have been laughed out of the room.