25. "Hate That I Love You" (feat. Ne-Yo) (2007)
Having co-written Rihanna's 2006 ballad "Unfaithful" and been dubbed a "genius" by the then–19-year-old in an interview with MTV, Ne-Yo helped craft three tracks on 2007's titanic Good Girl Gone Bad. None were as big as this Grammy-nominated gem, which updated the soul-duet ideal for the mid-2000s R&B landscape by combining breezy guitars with bittersweet harmonies. "The best way to express an emotion like love is through storytelling," Ne-Yo told Vibe in 2008. "It makes it more, 'I can relate to this character in this song, because I've been through something similar.' ... I come from a generation where saying 'I love you' is something you say to a girl to take her pants off. But I know the weight of those three words." M.J.