So I did some research.
I work in an office with all men, I am the only woman who works in the office aside from a couple of secretaries and assistants. The guys with whom I work are professional, young, attractive men. When I asked them, they all said without a doubt they pay of the first date, no questions asked. I have to say, going to work doors are always opened for me, I have never paid for anything (coffee, drinks etc.) and the guys go out of their way to act like gentlemen. This is not because they are trying to get in my pants, it is because they were raised to treat a woman with respect. Why would one person ask out another and then expect them to pay?
This being said, clearly is it a matter of preference. There are plenty of men who would not dream of letting a girl pay on the first date, and clearly, plenty who feel it is necessary the girl pays. Different strokes...