This is juvenile...

Nina Hagen
Melody Gardot

Ruthie Foster would have to be one and also The incredible Billie Holiday, Sweet nectar from the gods!

Eyes open? > DIana Krall

Eyes closed? > Oleta Adams

RELAX! Diana's voice is amazing but her looks add to the allure. Oleta's voice alone is absolutely rapturous! Both are lovely ladies...

I forgot Annie Lennox-"Sweet Dreams are Made of This"

Years ago I fell in love with a local singer named LoriSue. I pursued her until she gave in and said "yes". She's treated me like a rock star ever since. And I'm not kidding! Joe 

+1 for Sade.
+1 for Norah Jones (been listening to her music a LOT lately).
I’ll toss in Lydia Pense circa 1969 for nostalgia’s sake.

Carmen Gomes
Ana Popovic

Sarah McLachlan...

I should be her drummer and husband. 

I would have to say give me some Ruthie Foster, ever since the first time I heard Mamma Said it was on since then!!

Grace Potter. 
She has\d so much of an earthmother goddess vibe when I saw her. 

Michelle Phillips

Michelle Phillips in the Mamas & Papas days.

Can't forget early Mila Jovović before smoking and mediocre acting took her voice.  https://www.youtube.com/watch?v=fQ_I_aWsaRM

@oregonpapa , never heard of Carol Kidd before. Thanks. I love Crystal Gayle's version of When I Dream, too.

My answers: As a kid, Linda Ronstadt. No contest!
Now, when I imagine myself young again, I think it would be Eileen Rose.
https://www.youtube.com/watch?v=4faPY-NJtB0

Great lyricist. 

Eva Cassidy , hands down.
Her rendition of Over The Rainbow has no equal &  everything else she did in her short life span was superb too.

Hope Sandoval

Katherine Jenkins.  Absolutely Angelic in every way.

PJ Harvey.

Second Debbie Harry and  Linda Ronstadt

Hannah Reid from London Grammar. Heard her voice before I saw her angelic beauty. She is frail yet strong in voice...speaks so well in that upper crust Brittish accent.....perfect. Seen London Grammar live 3 times.....heaven on earth. Sade or Sara K are my second choices. Interlude Live is one of the best love songs ever written.. Oh yeah who could forget Bonnie Payne from Elephant Revival....Raven is a must listen. 

Sade Adu

Eva Cassidy, without doubt!

Diana Panton

Melodie Gardot.

"Happy birthday, Mr. President..."

Marilyn Monroe

Nancy wilson. 

Sandy Denny.

ZZ Ward

I third Sade plus 
Beth Orton
Melody Gardot
Carole King
Etta James 
Nina Simone
Sara Vaughn
Ella!!!
Beat that Stevie Nicks????
IMO

I second Sade. Classy woman and sexy as hell.

No-one mentioned her. She died very young. She is already very ill here and she knows it. Let's listen..
https://www.youtube.com/watch?v=2-Y_4tW0jnw

Its all about the character of the voice, isn’t it? There cannot be one female vocalist fortunately:) Here is the list in no particular order:

The one and only - Tina Turner
Aretha Franklin
Whitney Houston
Edith Piaf
Janis Joplin
Stevie Nicks

My apologies to that person who likes Diana Krall. No offense to you but her voice is like very smooth and well churned vanilla. But its vanilla... esp amongst the great vocalists others have listed here on this thread. Diana Krall is like going and visiting stunning Venice on a massive cruise ship. Its as lacking in character as the fake Italian villas scattered all over Newport Beach coast in CA. There.

How about  Sara Bareilles from "Jesus Christ Superstar"? Such a beautiful Voice I don't even need to know what she looks like.  

Raquel Welch. Who cares if she can sing. 

@inna I

 Klipsch my man, Klipsch........lol

Women are like loudspeakers - give them the right signal and they will sing. What will become of you is another question.

I’m "Stuck On You," Joss Stone

@frogman---Ha, good thing women don't feel that way. There'd be a lot of homeless musicians ;-) . One performer who has left a littered field of past relationships is Lucinda Williams. She has been through more marriages and boyfriends than a movie star from the 1940's and 50's. 

You don’t want to live with a performer....trust me 😊

@audioman58---Apparently Keith Richards finds Norah very attractive. The two of them did a duet on "Love Hurts" at the tribute show to Gram Parsons at The Universal Amphitheater in 2004. I was in attendance, and watched in horror as Keith couldn't keep his hands off her---he was all over her. It was creepy---he was acting quite lasciviously, and she looked very embarrassed. I was embarrassed for him. Keith, dude, act your age, not your IQ.

@grannyring -  Can we share?

Juvenile indeed, but

Yuja Wang

(plus Hilary Hahn, plus Julia Fischer)

Norah Jones is pretty laid back , attractive,and seems pretty 
mild mannered . Everyone likes something with different twist.

Aimee Mann (songs)
Amel Larrieux (Looks and vox)
Adriana Evans (Looks, also jazz singer Mary Stallings little girl)
Rachel Z (musicianship.and when she was a bit younger - (Just call me Shallow Hal)
Sade (booty..WHAT???)
(You guys have all my other picks).

Yes i'd give 1970s  Debs a run round the block. 

Nobody for Debbie Harry?

Emmylou Harris, The Tulsa Queen....