I celebrate Christmas. No doubt about it. I think I've made myself clear on this point. If someone tells me "Merry Christmas," I reply in kind. Likewise if I'm told "Happy Holidays," which is my standard year-end salutation. I think it is perfectly practical to celebrate the season without any kind of religious reference. It is true that the holiday is steeped in religion, even as there are a thousand reasons to keep it secular. The very word "Holiday" comes from "holy day." The songs we sing are largely religious - a fact which has absolutely no influence on how much I hate them, our Christmas trees symbolize nothing religious as far as I know, but stars or angels on top certainly do. Even Santa Claus, the secular symbol of the holiday has religious roots. The truth of St. Nicholas aside, the mythology of the real person is an example of something good that people do, and an excellent model of generosity to follow. In a silly way, Santa Claus is the reason for the season!
It is impossible to completely extricate religion from popular culture. So much of our language and reference points are tied to one religion or another. Our days are named for a seemingly random and multicultural assortment of gods (Odin, Thor, Saturn, Tyr), our planets are obviously influenced by Greek and Roman mythology. Art, architecture, music, family structure, politics - all of these bear the mark of religion's influence. I find it nearly impossible to refrain from saying "Bless you" when someone sneezes. I know that no demons will enter a soul. I know that there is no god to even provide the blessing. Further, sneezing is extremely common and not particularly uncomfortable - coughing is an indication of a far more serious problem, but we usually ignore all but the most severe coughs. But when anyone around me sneezes, whether I know them or not, I say bless you. I even say it when my dogs sneeze. In fact, I feel slightly, irrationally insulted when I sneeze and get no bless you. It makes no sense, but it is a social convention that I have little or no desire to remove from my life.
Likewise, I have no desire to remove churches from the landscape. Religious art does not offend me. I find most Christian rock boring and insipid, if not obnoxious, but there is the occasional band with strong Christian messages that I still enjoy. Is it possible for religion itself to become completely secular?