My ex-boyfriend wasn't very vocal. But that was mainly because there was either somebody else in the room (college dorms, what do you expect?) or somebody in the next room.
2nd guy, well I honestly don't even remember it much. One night stand sorta situation
3rd guy... First time I had sex with him he moaned out a few hearty Fuck Yeah!'s. I tell you what, it made me feel damn good. Does a lot for the ego to hear a bit of approval like that.