Well, hold on a minute. Santa and such is good for growing imaginations. I don't know many children who grow up hating their parents because they "lied" to them. I grew up with Santa, and I don't resent my parents.
I think it's a matter of concious. If you think Santa does harm, don't teach that to your children. But to tell other Christians they can't do the Santa thing, is to cross the line over to legalism.
Santa Clause is an idol god
I specifically remember the first Christmas that I didn't believe in Santa Claus. I couldn't have been older than 5, because we were living in a house that we moved out of when I was 5. I may even have been 4.
We left for Christmas Eve services, the tree was in the livingroom, but there were no presents. When we got back from Church, there were presents all around the tree. My parents said, "Look! Santa came while we were at church."
At that tender age, I knew there was no real such thing as Santa. My brother -- he was 6 or 7 at the time -- was very excited, so I didn't say it out loud, but I pulled my mom aside, and said, "I don't know how you guys did this, but I know it was you. There's no such thing as Santa Claus."
Looking back at that, it's kind of sad to think that I never really had a childhood. Maybe that's why, since I was about 26 or 27, I've been so immature as an adult.
Now that I have a 2-year-old, it will be interesting to see what he thinks about Santa.