I agree about giving everybody respect when you first meet them, but if they're not as worried about PC as others may be, then an occasional joke is perfectly fine.
For example: (as I so poorly worded in a different topic.)
I myself have been known to joke with my female friends, saying things such as "Pretty big word for a chick." or "Why aren't you in the kitchen?" Now, most of today's famous chefs are men, and, a good portion of the most intelligent people I know are women. . . The thing we're laughing at isn't a "sexist" joke, but rather how wrong that statement is now.
Not long ago, women were the ones doing all the cooking. Not long ago men were generally the only ones educated- ah, sorry, rather, white men. The reason we laugh at those sorts of statements, and trust me, they have plenty for men, is because there is honestly people who still believe them to be true. Of course, I wouldn't say "Pretty big word for a chick." to anyone I had just met, but I don't change my choice of words when talking to those friends in public. If somebody gets offended by what I'm saying in a personal conversation that they have no business listening to, then tough.
The fact of the matter is that most people I've met that are concerned with being PC, are caring too much about what anyone who hears them thinks, and too little about what who they're talking to thinks. Respect though, which is quite a different subject I assure you, is about having empathy and not offending the people you're interacting with.
Okay, I'm sure I worded something in there in such a way that could insinuate something offensive, or stupid. . . Have at it then D&D!