For 8 years I worked in a university with international students, many significant others/friends in my life come form all walks. I guess I am probably the least PC person I know. I don't say certain things because 1) they show ignorance 2) they are intolerant and 3) grouping ANYONE is against my own personal ethics/morals/philosophy. I think that in general people are just to caught up in grouping and as a result there are a great many misconceptions about any particular group, ethnicity, or gender. So, my take on this is, I judge a book not by it's cover, but by the story inside it. If everyone took a few more minutes to look beyond the cover and the title they too may find that there are more interesting things in the world that those 'groupings' titles or categories.
Years ago, my very southern grandparents would refer to African Americans as N..... does this offend me? Yes, did I know why? No, I was a child but I did know enough that it "hurt" me to hear the tone of their voice when they said it. Am I being PC by saying African American? No, I don't think so, that is what they prefer and so that is what I say. Am I saying it to be correct? no, but to provide a level of respect and consciousness of what and how they feel.
For our Arabic friends, I have been on the recieving end, I look Palestian or Egyptian, my dress and speaking a little Arabic caused me no end of grief in some situations so realize both sides of the equation.
IMHO, I say what I have to say, if someone is offended unintentionally by my saying Merry Christmas or whatever, I most humbly apologize. But it is their hang up not mine, The gift we have is to be kind and tolerant, to forget labels and judgments and just do what we do and say what we say. What is it they say.. .walk a mile in their shoes -- then decide if what you say is just correct or politically correct.
sorry, can you tell my minor was in cross cultural communication? :-) I am off my soapbox.