5. Tina Turner, 'River Deep, Mountain High'
Phil Spector made Tina Turner sing "River Deep, Mountain High" for hours on end until she got it just right. "I must have sung that 500,000 times," she said. "I was drenched with sweat. I had to take my shirt off and stand there in my bra to sing." The work paid off. The track is arguably the finest produced by either Turner or Spector, though at the time, it was a relative disappointment commercially. "I think when it came out, it was just like my farewell," Spector told Rolling Stone in 1969. "I was just saying goodbye, and I wanted to go crazy for four minutes on wax."