I recently read that Mark Twain loved Christmas, and would go all out on decorating his house in red, green and white. The notion that one of the most famously cantankerous atheists became the Gilded Age equivalent of a dad setting up elaborate light displays at Christmastime makes me smile to no end.
It's time we admit that what we really like about the holiday season is secular. My old minister once said that the idea of "putting the Christ back in Christmas" seemed kind of silly because Christ was kind of shoehorned in there in the first place. There is nothing in the Bible that gives December 25 as a date for Jesus' birth, and in any case (more devout people may correct me on this) Christmas is nowhere near an important Christian holiday as Easter.
In fact, most of what we think of as parts of a traditional Christmas dates back no earlier than the Victorian Era (i.e. when Twain was dressing up his house). Carols and turkeys and presents are not exactly Biblical. (BTW contrary to popular belief, the red-suited image of Santa was not created for a Coca-Cola ad).
I can also remember reading about how Isaac Asimov (another resolutely secular writer) speculating about whether the Christmas Star was actually a supernova. Asimov wasn't trying to snark on Christians, he was just participating in a fun thought exercise. If we insist on Christmas being entirely about all Jesus all the time, we lose that sense of fun. Does it even have to be called Christmas? I guess it could be called Yuletide or the Winter Solstice, but it's all about the same thing: half the world gets cold and dark, and that's reason to huddle together with bright lights.
That said, I think Christmas is still, in a way, sacred. I think even a secular world can benefit from the idea of sacred time - the idea that slowing things down makes the time more meaningful. One thing I love about the actual Christmas day are the stray moments of silence. Even in a household full of people there are usually at least a few moments at Christmas time where everything is still and peaceful.
Which brings me to Linus and A Charlie Brown Christmas. When they made the special nearly 50 years ago the "war" on Christmas was about creeping commercialization - a war that Christmas has pretty much conceded at this point. A Charlie Brown Christmas was specifically about combatting the idea that Christmas was all about presents. This is why Linus' recitation of the Gospel Of Luke was so radical. Take out the Christ part of Linus' speech and what do you have? "Don't worry, be happy, and be good to each other." That's sacred enough.
Or, to put it another way...