I find female vocalists very pleasing. Feist, Cat Power, Amy Milan, the girl that sings in "Lazy Line Painter Jane" has her own band that is really awesome, Annie, Kim and Kelley Deal, the girl from Cub, the Vaselines, Shop Assistants, Rilo Kiley, Sleater-Kinney, Bratmobile, Huggy Bear, Heavenly, etc, the girl in The Kills, Jon Spencer's wife, Justine Frischmann (Elastica), Poly Styrene, Jamie Stewart (I kid, I kid).
I find that of singers where I really say "Wow, I love their voice" almost all of them are female. However, I seem to prefer the lyrical content of misanthropic burnt-out men (The National, Spiritualized, LCD Soundsystem, etc.) but that's just cause I can like, totally relate man.