You mean Humperdinck Vandersnatch. Horrible voice.
Now Anna Torv in Fringe, much better.
Tim Curry. God, I could listen to him read the phone book.
George Sanders. What a voice.
The former, for me. I know that plenty of people find particular foreign accents sexy or attractive, but that’s never been my experience—although there are some British male voices that I might find sexy if I were oriented that way.
Seth MacFarlane.
Say what you will about his animated shows, but his speaking voice is wonderfully deep and smooth and I would KILL to talk like that instead of my stupid voice.
Barbara Feldon and Suzanne Pleshette. Love me some deep-voiced women.
Seconded.
Oh, yeah. That guy’s voice is pure liquid sex.
Alan Rickman, too.
Will Arnet
Best ever and sexiest Batman voice [sorry, Adam West].
Can anyone else make ‘club sauce’ sound so sexy?
Doubt it.
Hey!
When did you hear my stupid talking voice 
Oh, definitely.
Also Keira Knightley, Gemma Arterton and Kate Mulgrew.
Then you’d love Kathleen Turner!
Uma Thurman
Michelle Forbes.
The only voice I’ve had that reaction to is Claudia Black, but I now realize that’s more any woman with that accent and general pitch range.
Peter Dinklage.
Oh, yeaaahhhhh. Her too.
Garrison Keillor has a wonderful voice, but I’m not sure I’d call it sexy – probably because I’ve seen him.
My sister had a Cockatiel that would sing and dance whenever Garrison’s voice came on the radio. When Garrison stopped talking (or singing), the bird would just stand there and look dejected.
Does sexy to birds count?
David McCullough has a great voice, perfect for talking about history, but I wouldn’t call it sexy.
The way Jessica Savitch could throw the odd “sh” sound into some of her words was…interesting.
Charles Kuralt’s voice could really boom and resonate.