What are your top 3 favorite female singers?

I'm not quite sure how I picked up a cassette tape of Blossom Dearie all those years ago, doesn't matter. 

My girlfriend at the time who was a singer and musically trained at a conservatorium loved me for finding her,

Well you cannot have three faviurite singers, however you can have your favourite three singers. Mine are Callas, Frederika von Stade and Jessye Norman.

Annie Lennox.  

Françoise Hardy has been mentioned (several times!), so I will submit:

Cecilia Bartoli,

Carla Bruni-Sarkozy,

Diana Krall.