sexiest sounding female vocalists?

Shirley Manson of Garbage

and Free Dominguez of Kidney Thieves

although, there are a lot of other great suggestions listed above.

Toni Braxton and Anita Baker

I personally find female vocalist who try to sound sexy quite annoying. In many cases it's just a cover-up for a lack of talent. If you guys only knew what goes into the engineering process of recording, overdubbing, blending, pitch allignment,etc.; your queen might come off her pedestal in a hurry.

Angie Bofill and Dianne Reeves

Highly subjective,of course.

Here are two who haven't been mentioned yet.

Sarah Vaughn and Maria Calis