My family and I don't. We have no tree, no lights, not even a gift one is wrapped and given in our house.
We celebrate the Lord every day and feel we should not set aside JUST one day a year for him. As God did not put it in the Bible for us to do so. If he had wanted it to be done he would have made sure to have included it in his word.
But I think you will find this following link informative reading.