"Ain't no mountain high enough, ain't no valley low enough" -- this eternal hit, first sung in 1966 by Marvin Gaye and Tammi Terrelll, was inducted into the Grammy Hall of Fame in 1999. It became a hit again when Diana Ross put her own soulful spin on it in 1970, and has since been regarded as one of Motown's greatest classics of all time.
6. 'Ain't Nothing Like the Real Thing'
A single released in 1968 by R &B duo Marvin Gaye and Tammi Terrell, it is perhaps one of Ashford's most popular songs and launched Gaye's reputation as one of rhythm and blues' sexiest crooners.
7.' I'm Every Woman'
Chaka Khan made her mark on music history with this funky 1978 anthem. The hit, later covered by Whitney Houston, made it a chart-climber in the 1980s. It eventually reached No. 1 on Billboard's Hot Soul Singles chart, according to Billboard.com. With its soulful lyrics "I'm every woman, it's all in me, anything you want done, baby, I'll do it naturally," Ashford wrote a lasting classic that earned thousands of fans all over the world.