This doesn't seem to have posted the first time...
Recommendation: this book by Harry Maurer.
http://www.amazon.com/exec/obidos/tg/detail/-/0140171452 55 interviews (mostly edited down into monologues) with people about their sex lives. Maurer comes to this as an interviewer and historian, not a sexologist, and -- as far as I can see his hand in the results at all -- he's amazing. The people's voices jump off the page. I've read a fair number of books more or less like this one, and a lot of them seem to be mild porn for people who are comfortable buying high-minded books about sex but not, you know, porn. This is different; it's hot, but that's because it feels honest.
If you've ever masturbated to the Hite Reports, you need this book.
Uh, I know I'm not the only person on the planet who's done that; Alison Bechdel included it in an autobio story she wrote once.