I'll mention a few interesting voices, not necessarily sexy:
PEOPLE I LIKE LISTENING TO
Amy Grant - I'm surely the only poster to bring in a Christian recording artist :->, but she has this amazingly breathy timbre.
Daniel Schorr - yes, the (very) senior news analyst on NPR. I love listening to his little monologues. I also like the rare appearance of Henry Kissinger or Zbigniew Brzezinski.
Alanis Morissette, Anna Nalick, Karen O - elastic-voiced rock/pop femmes
Jewel - okay, her poetry is best left in the drawer, but "Who Will Save Your Soul" is a pop-singing tour-de-force...
Mika - ...as is "Grace Kelly"
Vienna Teng, Rachael Yamagata, Fiona Apple - piano pop songstresses
Chris Martin (Coldplay) - esp. "Politik" and "The Scientist"
Berfu Guven - cute-as-a-button anchor on "Business: Turkey" on CNBC
Cheng Lei - Shanghai reporter for "Business Tonight" on CNBC; breathy way of speaking that makes me tingle...
Dave Matthews, Jack Johnson - laidback guitar pop
Dido, Feist, Paula Cole - breathy, earnest-sounding
Heather Nova - in a class all by herself... I get dizzy listening to "Truth and Bone"
Neko Case - not a huge fan of her music, but what an arresting voice!
Beth Gibbons - lead singer of Portishead; pick any song from "Dummy"
Regina Spektor, Bjork - their accented vocal gymnastics are endlessly fascinating
PEOPLE I WISH I SOUNDED LIKE
Randy Owen - lead singer of the country band Alabama; ladies, listen to "Feels So Right" and try not to melt.
Paul Young - especially on "Love of the Common People"
Damien Rice - the raw fear of commitment he shows on "I Remember" is astonishing
Chris Whitley - R.I.P. ... but what a voice on "Big Sky Country"
Ian Astbury - lead singer of The Cult; "Fire Woman" would be my audition for American Idol if I weren't too old for it -- and could actually sing :->
Iva Davies - lead singer of the '80s band Icehouse; David Bowie without the affectations :->
Jeff Buckley - R.I.P. ... best rock falsetto ever? "Hallelujah" is AMAZING
Mat Kearney - some will say that Chris Martin is the successor to Jeff Buckley, but to me the real heir-apparent is this guy -- "Nothing Left To Lose" was a big hit a couple of years ago