Claudya's right. We don't know when Jesus was born but it is very doubtful it was in December, and the true original "reason for the season" was actually a pagan holiday! But with that being said, I have no problem with celebrating Jesus' birth on December 25th, and I have no problem with the idea that there may have been a pagan holiday celebrated at the same time that Christians have usurped to celebrate Jesus' birth. When I celebrate Christmas, I celebrate the fact that Jesus was born at all and the exact date of his birth is irrelevant to me. And to me a celebration involves other people to share it with, so for me it would be pointless and really pretty weird to try to celebrate Christmas on some day other than December 25th!
As for the commercialization, I completely agree with WIP on the extreme this has become. I too told folks a few years ago not to give me gifts anymore, but just to celebrate Jesus' birth with me instead. For several years now I haven't received any gifts and I spend Christmas with Christian friends. I don't miss the gifts. Of course, being true to the concept I also don't give gifts to others (and that is probably the real reason they don't give me any!) so if there is any material thing that I want, rather than hoping someone gives it to me I simply buy it with the money I saved be not partaking in all the hyper-commercialism.
When Christmas fell on a Sunday recently I was astonished that so many of the local churches in my area cancelled their Sunday morning worship services! The reasoning among the pastors and elders was that people aren't going to get up and go to church on Christmas morning because they'll all be too busy with "family stuff" which I think was really code for "sobering up from the night before and serving the god of wrapped presents". It was shameful! I just couldn't believe how many of them did this! But there was at least one church (one that I know of anyway) that rightly saw the stupidity of this and continued with their service. They set an all time record attendance that was WAY past the previous record!