Guitar Heaven reprises the cameo-heavy formula Carlos Santana has used since 1999's Supernatural, only this time the celeb vocalists lay into an assortment of classic-rock covers. The performances are mostly faithful to the originals, and Chris Daughtry gives Def Leppard's "Photograph" a credible kick. But only about half the songs get any traction — "Back in Black," where Nas rhymes beside anonymous rock-chick vocals, sounds like a Super Bowl halftime show. The best turn is from a smaller name: India.Arie, who finds the soul in "While My Guitar Gently Weeps." As for Santana? Smooth, as usual.

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“Help Me”

Joni Mitchell wrote and recorded this song for her album Court and Spark, but she had to switch from her regular band to make the song sound exactly the way she wanted. "I had attempted to play my music with rock & roll players," she told Rolling Stone. "They’d laugh, 'Awww, isn't that cute? She's trying to teach us how to play.'" Mitchell switched to a jazz band, Tom Scott’s L.A. Express, and scored the biggest hit of her career in the process.