I am getting into Lady Gaga, but wouldn't consider her a great voice. A great curiosity.
Carla Bozulich is awesome.
Anyone mention Edith Piaf yet? Marlene Dietrich? Ute Lemper, for that matter?

Anyone heard of Canadian singer Oh Susanna? Sort of in the Neko Case area, I think. This video's good but the album to look for (with this song) is "Johnstown." Not a bad song on it.