Favourite Vinyl female and male vocals

All great choices above, especially the great Miss Ella IMHO.

Don't forget the incredibly talented Laura Nyro. Although she is best remembered as a composer she had an incredibly earthy yet sweet voice.

Great list, I have'nt heard Johhny Hartman , I will follow that up. Some other suggestions I can't see so far:
Karrin Allyson "Blue", if you can find it.
Nowone mentioned Frank Sinatra, just anything, particularly from the Capitol years
Lorna Hunt "all in one day" again if you can find it, my favourite record.
How about some classical, opera or Leider, Jessye Norman, Janet Baker, Maria Callas, placido Domingo. If you are going for Leider, I would go for Richard Strauss to start, Janet Baker or Elizabeth Schwarskopf, hard to beat.

Try these:

Elliott Smith
Mary Gauthier