I have a thing for skill. Skill is sexy, and since the riding style required by sportbikes demands more skill, it's naturally sexier to see a girl on one of those than on a cruiser. Same thing with a girl who can drive a stick shift well.
Personally, knowing what I know now, if I were buying a bike all over again, I would buy a bike that was designed around riding on the type of roads that I have in my area, whether it was a cruiser, a sportbike, or a dual-purpose.
i ride, I have a crotch rocket a GSXR 600. there is about 30 guys I know that ride and 3girls within the last 2years. now about 4 more girls are on the bike and its soo damn hot. since I'm a sports bike guy. I like to see a girl on one too, but to me as long as you are riding. your riding sexy. lol
I LOVE motorcyles. I love guys on them and I love them for myself. I almost bought a Harley about a month ago. But we were out of state and didn't really have a way to get it home. Bummer. I prefer Harley type bikes over the rest, my choice number 2 would be a crotch rocket.