Wow... lots of votes for Kayla, I see. That was unexpected... I do have to veto that one though, my little sister's name is Kayla. And Caitlyn is the name of a very good friend's daughter... I do like that one as a name say, for my own kid, but I don't think it's "sexy" necessarily.
Most of the names I find sexy are very smooth flowing, typically no hard consonants... elvish I guess you could say, if you're into fantasy books. Amelia, Amy, Anna (pronounced ahh-na), Angelina (yeah, probably because of Mrs. Jolie), Natalie...
From previous experience, I'd say that most Sara's I know (no 'H' at the end) have been sexy or attractive... and then there's Darling Nikki... I think that one's a combination of the Prince song and the fact that most Nikkis I've known have been gorgeous! Pined over several Nikkis during high school, and damned if my uncle, who is like a brother to me, didn't date three different HOT redheads named Nikki. In fact... most Nikki's I've known have been redheads, for that matter.
Oh, Jennifer is another name that's synonymous with attractive women throughout my life... I really cannot think of a Jennifer off the top of my head that's anything less than an 8 on a scale of 1-10. I knew several Jen/Jennifers in high school and met three more during college, not to mention the future possible Mrs. Shizukanas... Jennifer Aniston and Jennifer Love Hewitt.