Yeah, funny. I would probably try not to get into any situation that involves me showing my car to strangers, including buying sedate and unassuming cars.
Nevertheless, if asked, I probably would, though I second Alex on that part about not putting myself in danger. So, for the poll, I'd probably vote yes, though it really goes for either the opposite sex or the same sex. No big deal.
As for girls, well, I don't really care either way (not to mention my girl friend probably wouldn't appreciate it that much anyhow, but we'll leave that out of this hypothetical situation for now).
I would be much happier if any observer, male or female, had an interest in the car itself, rather than as some gauge of my monetary potential or something. Nevertheless, you can't expect everyone to be an expert. Either way, I'd just show them whatever I drive, if you don't like it, tough luck, get lost..

My would like to think that my sense of self worth, and worth to others, has little to do with what car I drive.