I am Jewish- I don't tend to get offended very easily by things like this, around this time of year people always say Merry Christmas, or have a nice Christmas or something to me and I just say "same to you" and move on. I did find it slightly amusing when I was younger and people would say something about whether I had been a good girl so that Santa would bring me nice presents and then THEY would get offended when I told them Santa wasn't real.
I didn't do it to be rude, I was just a very matter of fact child and my parents had told me very young that Santa wasn't real, so I didn't understand why all the adults made such a big deal about this fake person
Anyway- I mostly tell people to have a nice holiday season- this encompasses everything including the new year- but whatever you say to me is fine.
The only thing that does kind of offend me is when friends send Christmas cards- its one thing if you had Christmas cards made and you want to send that- but when you just go to Hallmark and buy me a Christmas card, you just as easily could have bought me a Hanukkah card and showed that you put some thought into it- but that only offends me with people who I know well who obviously KNOW that I am Jewish.