Any girl who's been out for less than 5 years is not even eligible to be considered one of the biggest of all time. Longevity and survival is what makes the legend.
1. Madge
2. Barbra
3. Mariah/Cher
(Whitney would have tied for 3rd if she hadn't destroyed the final 15 years of her career).
I forgot to vote for Aggie tho. 
