1. Metallica and Marianne Faithfull, "The Memory Remains"
Metallica's best original song in the past 20 years is aided by an unearthly rejoinder from one of rock music's greatest collaborators, eternal muse Marianne Faithfull. Her quote at the end is from The Misfits, not the band, but Marilyn Monroe's final movie.
2. Queensrÿche and Pamela Moore, "Suite Sister Mary"
An awesome and ridiculous band at their awesome and ridiculous peak. "Suite Sister Mary" is a ten-minute centerpiece of a Manchurian Candidate-esque concept album featuring a full, Michael Kamen-conducted choir serenading the titular character, a dominatrix-turned-nun played by Moore. Shockingly tame when considering the depths that Queensrÿche would later sink to.
3. Motörhead and Girlschool, "Please Don't Touch"
A punk-metal makeover of a mostly-forgotten rockabailly single, "Please Don't Touch" casts its performers as the Devil's answer to Marvin Gaye and Tammi Terrell. Motörhead never needed to duet with anyone, but they knew it was in their best interest to give Girlschool half of this song. When Lemmy and Kelly Johnson sing "Please Don't Touch," it's a dare and not a request.
4. Rammstein and Bobo,"Engel"
Rammstein let chanteuse and countrywoman Bobo lead them into the chorus over a perfect storm of froufrou krautrock and industrial riffing. The music video gives Bobo's lines to a child and owes its life to Salma Hayek in From Dusk Till Dawn.
5. Ozzy Osbourne and Miss Piggy, "Born to be Wild"
Forget about "Close My Eyes Forever." This is John Michael Osbourne's only duet that does not defang him or overwhelm his collaborator, found on 1994's Kermit Unplugged. Ozzy hasn't sounded like he's having this much fun since "I Don't Want to Change the World." The band is a little stiff, but maybe Ozzy just makes everything else seem that way.