Trey Songz's fifth album is his first to top the charts, and it makes sense: Chapter V is full of big ballads and bigger club beats that take dead aim at the pop mainstream. But Songz is at his best playing to his R&B base on songs like "Panty Wetter," when the Spanish-fly vapors fog up the ceiling mirror and he wraps his supple falsetto around lyrics like "Your panty-dropper has returned, and I'm goin' low."

Listen to 'Chapter V':

“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.