There are some really good, and expensive, fake trees about. I've dabbled with them over the years but you simply can't beat the real thing. The best thing by far, as krich mentioned, is the fresh smell of pine in the house, hmmm. Unfortunately the coming decades may see fake trees becoming the norm, who knows.
I was talking to the wife the other day about maybe buying a real mid sized conifer, planting it in a large pot, and leave it outside all year round except for a couple of weeks of the year when we bring it indoors to decorate. Then, after Christmas, put it back outside.