At least once a semester, I'll have a student from a poetry class ask about whether or not song lyrics are poetry set to music, and my answer is usually the same--it's not that simple, because the music has a lot to do with the emotional impact of the words. If I'm in a classroom with a computer and a projector, I'll usually pull up YouTube and show a couple of videos of odd cover songs to prove my point--Matt Weddle's acoustic version of "Hey Ya" is a good one, as is this kid's take on Soulja Boy's "Crank Dat." They seem to get it, once they're over the shock of the new version.
But music can be really effective in changing other contexts as well. Here's the latest I've come across--change the bouncy opening jingle to the tv show "Different Strokes" and you've got a very sinister show, real ABC After School Special material.
The guy who put this together says he filtered the video some to make it darker, but I don't think that was even necessary. The music makes all the difference.