I don't think you should lie to kids, in any way. It's just sends them a deep message that never leaves them. It's disgusting.
Unlike you, I was never told that Santa existed, since I'm Jewish. The guy in the mall -- Some overweight unemployed person. Now, my parent's still tried to convince me that the tooth fairy existed. It was extremely insulting. I said, okay, howabout I give you the tooth, and you give me the money. We both know very well that you're the so called "tooth fairy" . She responds: No I'm not.
So I stay up that night to prove it, and afterwards she still tries to convince me that she never tried to play the role of any ficticious charecter such as the tooth fairy. It was very confusing. I didn't wan't to believe in something so illogical and pathetic, but there I was, being told by someone I trusted to have faith. Luckilly I didn't. She still tried to convince me when I was twelve.
It just sends kids mixed messages. They're supposed to trust their parents. But lying to them gets kids into the pattern of blind faith, where they loose independence, and trust the word of close people rather than themselves. That's sadly, bound to lead to kids' who don't think for themselves, and pick up bad habits down the road.
I guarantee you, that all the druggees, loosers, and bums nowadays believed in Santa Clause, or the tooth fairy, or whatever, when they were kids.