The several (seven?) 3CD boxes in the Collected Dinah Washington prove her to be a real hero: Ella is technically a better singer, and Billie is more instantly recognizable, but Dinah owns you. (These are Collected but not Complete-- there is stuff available both earlier and later, but its muh more uneven). Classical/opera, my own view is that the greatest living voice of any gender is Jessye Norman, but her recordings do not do her justice. As to pop, I'm really impressed with Joan Osborne and Laura Love, both of whom have modest instruments but huge hearts.
