Vocally, I prefer more women.
There are plenty of legendary male voices (without going into opera
)... Otis, James Brown, Marvin, Ray, Roy Orbison, Chet Baker, Nat King Cole, Andy Williams, MJ, Prince... and that's without taking into rock, pop or folk musicians who have gentler/edgier voices. I'm just limiting myself to more... "classic" voices I guess.
But if I were to task myself with the decision of "listen to one person for their voice and their voice alone", my answer would always, always be Nina Simone... so I voted for women.