I really had to think about this one for a while. I typically refer to women as girls, particularly if they are around my age (30) or younger. I can't see calling a 70-year-old woman a girl in conversation. But I often find myself talking about a "woman" and I call her a girl. To me, it feels closer, like she's part of my club or something. I can also be found saying chic... often referring to a girl I think is pretty cool. "Woman" feels so official or categorical to me. Not to mention we're fighting for a term that has "man" in the title.

Girls and guys is usually the way I go.