I'm of the thinking that if i'm celebrating Christmas i'm gonna say Merry Christmas. And if you aren't Christian and somebody wishes you a merry Christmas don't get upset we aren't trying to convert you or anything!
I'm also kinda on the fence with this though because i think Happy Holidays is perfectly acceptable too! It is a group of holidays around that time with Thanksgiving, Christmas, Hanukkah, Kwanzaa and New Years, and maybe some more.
I think we should just not worry about what kind of greeting we get or give at this time or year, we should just wish peace, love and happiness to our fellow man regardless of what holiday we happen to celebrate! :-4 :-6