I don't have a set number of dates before I sleep with someone. I think I wait longer than most people do though usually at least a couple of months. I think it helps weed out the guys who only want sex.
I've never had vaginal sex and intend to wait until I'm married.
I do engage in anal sex, but only with a trusted partner I intend to be with for an indefinite period of time. The one time I did casual, it was a horrible experience.
As a guy - I had a reverse strategy. I found it better - and a lot less frustrating for me, to wait until the girl I was dating really wanted to have sex. But I didn't have endless patience either. There was no fixed # of dates - just went with the feeling.
When I was dating, it really depended on how well I knew the person to begin with. For example, if I was already friends or acquaintances with them before we went out I might feel more comfortable with them and sleep with them sooner than I would someone who just came into my work and asked me out or if a friend set me up on a blind date. Usually it takes a while to get me in bed though!