I've linked this remix of Carl Sagan and Stephen Hawking before, and it's just getting redundant at this point, but now there's actually a thread relevant to the song. Melodysheep posted a second one, now with 100% more Bill freaking Nye. Not as good as the original, but still damn cool.

As for the discussion at hand, if you do something interesting with it, it can be a really cool effect. Like Pete said, if you just use it to hit a note you can't normally reach, it's a bit like cheating.

And Che, god damn that video is great.