Re: Santa Claus -- Do your allow your children to believe in him?
We're Christian too, and we do Santa, because he WAS a real man. And doing Santa is keeping his spirit of giving alive, which is a part of the real meaning of Christmas.
My 8 year old figured it out this year. He wasn't too sad, especially when he realized that he now gets to be in on playing it up for the little kids. It made him feel grownup to be in on the secret.
On the flip side, we don't do the tooth fairy or the Easter bunny, because neither of those is based in truth.