Twice recently I have caught a few seconds of this one on the radio on the way to work. Both times I raced over to Mark's desk and borrowed his copy of Joni's "Hits" CD to do what I could to get it out of my head.
Possibly the greatest musical travesty of all time isn't a cover per se, but Kenny G's overdubbing of himself over Louis Armstrong's "What a Wonderful World." I will actually confess that I've never heard it, but I'm willing to take
Pat Metheny's word for it. This one made the rounds several years ago, and is some of the finest vitriol I have ever read. I consider it must reading.