Into the Woods is probably my favorite musical. It's a close call with other Sondheim, who is really the only Broadway composer I can listen to repeatedly and often. I saw the show on Broadway twice, once with the original cast and then again when Vanessa Williams played the witch in 2002. I prefer Bernadette Peters, who opens this song in the original cast before it becomes an ensemble piece.
But what's so effective about this song is its quietness, which is why I often would rather hear a singer alone perform this. The haunting lyrics warn the listener in that way Sondheim does so well. (See "Not While I'm Around" for another prime example.) Children will listen, Sondheim tells us, but not to lectures and rules. Rather they listen and learn those things we wish they wouldn't: Careful before you say "Listen to me," and it's all done to a lilting lullaby of a melody.
Here's Mandy Matinkin hamming it up on Larry King:
And here's Bernadette in a live performance: