I am of the extremely strong opinion that Christmas is far too commercialized and has been for many, many years (see the original Charlie Brown Christmas Special). We have forgotten, in our greed, that it is supposed to be a day to celebrate Family.
I also feel that Christmas has become as much of a secular holiday as a religious one. It's part of what America was built on and, as America has become more diverse, we have all still celebrated Christmas and wished everybody a Merry Christmas to boot.
Speaking of which, why would wishing anybody a Merry Christmas be offensive? I may not believe what you believe, but the wish is for happiness and merriment. Who would want to turn down such a wish? I would greet a Happy Chanukah or any other such greeting with the same sense - it is a wish of good will.
We live in a melting pot of cultures here in the United States and not all of the population is Christian, but many still celebrate Christmas and spend that time with families, others see it as an excuse to get more stuff.
I see it as a time to celebrate family, because isn't that what the First Christmas was all about? It doesn't matter if you believe that first story as fact or not because the story is a sweet one that reminds us all to celebrate the family that we have.
So to everybody: