I really think it's unfair to give the title of 'worst ever' to a compilation album, and in particular, a rock music movie album (the competition is too fierce in that genre to pick just one winner anyway!); I would prefer to give the award to excellent bands who, either by hanging on too long, or just by accident, produce such an incredibly bad LP that, momentarily, you have to question whether or not they were as good as you thought they were. This is why these two albums always come to my mind in these discussions:
Naturally, I don't expect the agreement that the FM soundtrack garnished, but damn, these were a couple of disappointments!