I think all singers 'ranked' in this video have wonderful voices in their very own right.
Please take your time and try to enjoy the whole video, listen to all the small samples I picked carefully to present each singer's voice in the best possible light available, and then try to form your own opinion (and possibly post it as a comment, ).
Don't take the 'ranking' too seriously, though, it's nothing else but the personal opinion of a slightly conservative listener of pop music.
The order of the singers in this medley is heavily influenced by the way public poll websites like ranker.com , rateyourmusic.com, thetoptens.com, therollingstones.com etc. typically tend to 'rank' famous singers.
I tried my very best to include the most famous singers from many different generations - 1950s - 2010s , and from a wide spectrum of different genres.
What does your very own list of your favourite female singers look like ?
http://www.ranker.com/list/best-female-voice-ever/silurus-glanis