{{{Jess}}}
As a parent, I'm torn. I don't want to be a curmudgeon denying my child the Magic of Christmas, but OTOH I don't want her remembering her discovery of the truth as painful and embarrassing almost 20 years after the fact!
Believe me, Christmas isn't necessarily less magical because you don't do Santa. What filled our house with magic was the beauty of the holiday and the excitement of my parents in being able to give us what they never had and knowing that they picked out certain things for you personally. Also, then you can have presents arrive under the tree little by little, and shake them furiously wonder what they are. And siblings can give each other presents without some bizarre logical leap.
Also, even though I would never do the Santa thing with any potential kids, I don't really see it as a question of lying. But since I never experienced the whole Santa "betrayal" thing, I guess I can't really say. You should do what's in your heart.