I find this whole thread very interesting, as I was raised in a home where Christmas and Easter were never 'celebrated.' When I say 'celebrate', I mean Santa, Christmas tree, decorations---all that lot. My parents were ( and still are ) against celebrating it for all the reasons that have been previously mentioned in this thread. We, did, however, receive gifts from relatives, and having a big Christmas dinner is still a family tradition. Nowadays, some of my siblings and I have taken it upon ourselves to give gifts to others, as we began to feel bad about always being 'giftees' and not 'givers.' My parents still do not give gifts.
Coming from this background, my thoughts on celebrating Christmas are this: I totally understand where those who choose not to celebrate it are coming from, but I also think that there is truly no harm done in celebrating it, as long as its real meaning and purpose are kept. As I see it, it is a special time for family and friends to gather together and show their love for one another---what is so 'evil' about that? Christmas tree or no Christmas tree, Santa or no Santa, I enjoy Christmas because it is one of the only times of the year that my entire family---extended included---actually sits down to a meal together and a time of fellowship. We are not worshipping some pagan god or goddess, with dances and rituals around a Christmas tree.
I think everyone should just follow their own heart and convictions concerning the matter. If one feels that God is truly telling them not to celebrate Christmas ( as my parents felt ), then they should'nt celebrate it....that's fine. However, if one has no such conviction, then why should they let someone else make them feel guilty for something God has given them a clear conscience about?
It reminds me of some verses, written by Paul I believe ( I'll see if I can find the verses later ), in a New Testament book. He was writing to a group of believers concerning whether it was ok to eat meat sacrificed to idols. Basically, he left the choice up to the individual believer. He didn't say eating such meat was sinful---all he warned against was causing another believer to stumble. I think sometimes we overanalyze things. I think we should stop overanalyzing, and just leave it up to God to show others whether or not celebrating Christmas is ok. Celebrating or not celebrating shouldn't be forced on anybody. Celebrating Christmas is not akin to those clear-cut laws like, Do not steal, Do not lie, Do not murder, etc, etc. It's a bit different...