This is a matter of opinion, yet please be objective. Don't list Miley Cyrus or Hilary Duff...
Honorable Mentions: Mary J. Blige, Kelly Clarkson, Christina Aguilera, Fantasia, Donna Summer, Carrie Underwood, Gladys Knight.
1O. Dionne Warwick [See: "Promises, Promises", "I'll Never Love This Way Again", "Don't Make Me Over"]
9. En Vogue [See: "Hold On", "Don't Let Go", "Giving Him Something He Can Feel"]
8. Patti Labelle [See: "Lady Marmalade", "If You Asked Me To", "Over The Rainbow"
7. Aretha Franklin [See: "Freeway Of Love", "Since You've Been Gone", "Eleanor Rigby"]
6. Celine Dion [See: "Where Does My Heartbeat Now", "It's All Coming Back To Me Now", "My Heart Will Go On"]
5. Chaka Khan [See: "Through The Fire", "Disrespectful", "Sweet Thing"]
4. Trisha Yearwood [See: "This Is Me You're Talking To", "Georgia Rain", "In Another's Eyes"]
3. Leona Lewis [See: "Bleeding Love", "I Will Be", "Footprints In The Sand"]
2. Whitney Houston [See: "Saving All My Love For You", "I Will Always Love You", "One Moment In Time"
1. Mariah Carey [See: "Fly Like A Bird", "So Cold", "Lead The Way", "Emotions", "Hero"]