I think I'm a unique case. See, most guys like to pay the bill on the first date to impress the girl, and then move into a comfortable back-and-forth type of agreement, tit for tat if you will.
I will only pay for the first date if I explicitly asked her to join me for dinner, or whatever the case may be. I'm not going to, for example, invite her to a baseball game or a movie and then make her pay for her ticket!
If it's something, say, like an art museum that we both wanted to go to, and we'd been talking enthusiastically for a while about it, she can pay for herself :p (This might be where I'm unique, I like to talk to girls and get to know them well before going on any type of "date", and my dates include things like art museums and the like)
Once I'm in a settled relationship, I take joy in spending whatever I have to make both myself and my partner happy. I'm not greedy (not that I have a lot, by any means!), and I don't mind paying for anything that will bring us both enjoyment.
That being said, I expect that my partner will have some type of income. As it is in my case, I generally date girls based on their ability to read and converse meaningfully. For that reason, I think it's fair to say that they tend to have their own income; and if they don't... I will just teach them how to be a professional freelance writer! :D