While I do believe that this holiday is over commercialized we do let the children believe in Santa. We do have an "elf on the shelf" and it probably does make them behave a little better, but we stress good behavior all year, not just at Christmas. The children only (and I say only because everyone I know thinks I'm being stingy) get three presents a piece and one of those is a "Secret Santa" from one of their brothers or sisters (this is our way of saying the holiday is also about giving), and yes, two of them got one piece of coal in their stockings last year because they did not listen as well as they should have.
I guess I don't see the harm in believing in Santa as long as you set the "limits". Santa isn't what makes Christmas about presents, it's the adults that lead the children in that direction, which was the direction I was lead in, and that is not what I want for my kids.
Its fine not to believe in Santa, but I don't want to be you when your daughter is 3 or 4 and tells her friends there is no Santa.... You might have some upset parents on your hands for a bit.
ETA: I'd like to add that we are christian, and go to church. The kids also know why we have Christmas, and it's about celebrating the birth of Christ. It's possible to have your cake and eat it too here.