The first battle in the real war on Christmas is Black Friday. Or, in some stores, it even spills onto Thanksgiving Day now. Never mind that economists have shown that the deals on the whole are not necessarily any better than other times of the year, by the way. I am going to try not to turn this into another tired, anti-consumerist rant. But I am going to float the idea of ceasing to give gifts (or at least radically curtailing the practice). You can take it or leave it, it doesn't really matter to me, but it is worth considering.
I am sure you have heard dozens of people arguing about the consumerism of Christmas, how it detracts from the reason for the season, and what-have-you, so I am not going to rehash those arguments. I'm not even sure who is in the audience here, so I don't know if it is relevant to anybody.
But I think it is relatively uncontroversial to say that "consumerism" is an attack on "Christmas". It is a far more insidious attack than removing a Nativity scene from your community Winter Celebration Display because it is a fundamental attack on how you perceive Christmas, while the latter is just some absurd excision from some crappy art display. Nor is saying "Happy Holidays" a real assault on Christmas: Christmas is the only holiday people actually celebrate at this time of year.
If you are Orthodox or Catholic, you need to be in church on Christmas because that is what the holiday is . Christmas is not about staying in early with your family and opening presents. The perhaps more controversial thing I am going to suggest is that, even if you have children, you do away with presents. We all "know" that Christmas is not about consumerism and that consumerism is part of the war on Christmas. Children often sap our resolve, unfortunately. Why should they, though? You don't need to buy "stuff" to show them you love them, especially not if the cost is teaching them the wrong thing about Christmas. There are millions of non-Christian children in America whose parents don't buy them any gifts in December and they do just fine. Stop participating. They'll be better for it.
Okay, I don't mind a couple small gifts, nor would I ever tell somebody not to give some token out of love that they know will be sincerely appreciated and want to use the opportunity of Christmas to express that love. Nor am I going to say that, if your family needs something specific and you found a good deal on it, you should not purchase it "for Christmas". If people want to talk about what gifts they gave and received on Christmas, I have usually talked about those small tokens which I have often ended up purchasing rather than discussed how Christmas is a religious holiday so we don't usually give gifts, but I might change that.
If everybody followed my advice, it might have "devastating effects" on the American economy. Tough nuts. The status quo is devastating to American consumers and possibly their eternal souls. If you poke around discussions of people in financial trouble on reddit (see /r/personalfinance and /r/frugal), you see dozens of people in rather dire financial positions who think they need to go into $1000 of debt for Christmas just... because. Not so much around this time of year, but at other times of the year, you see people discussing their Christmas debt or planning for their Christmas debt (and it's debt, not expenditure).
One thing I do recommend: Christmas is traditionally a time for almsgiving. Give money toward feeding the hungry, sheltering the homeless, providing medical care for the indigent, and, yes, giving gifts to needy children.
 Many types of American Protestant are excused from this responsibility because they, historically, do not believe in Christmas, Easter, or any other feast. The only re-acquired them because the pull of paganism is so strong. Not having any way to actually celebrate the holiday (esp. since they were completely non-liturgical), they will not actually celebrate Christmas as a religious holiday and, if Christmas falls on a Sunday, may cancel their Sunday services. However, these are typically the loudest voices in the matter of the "War on Christmas", which is perceived as taking a creche out of the Winter Festival and saying "Happy Holidays".