My mother, who would now be 97 if she were still alive, apparently was teased as a child for believing in FC. So she made sure none of her children thought he was real. That didn't stop us having stockings etc etc and I don't think knowing 'it was Daddy really' reduced the fun of it. Like other contributors, I have doubts about any kind of dishonesty with children - I guess most of them cope fine when disillusioned, but for a certain proportion it is devastating and personally I don't think it's worth the risk to those few. So my children also always knew it was Daddy and Mummy. I actually don't know how all my DCs have handled it but certainly one has taken the 'FC is true route'. However he lives in the Middle East and last year ordered most of his presents, including FC presents, to be delivered to me in the UK as I was going out for Xmas.
Unfortunately the luggage system at Heathrow broke down and most of the luggage for my flight on Christmas Eve, including mine, was left behind. So I arrived in the early hours of Christmas morning sans presents. My son had a few things so we faked a note about problems in the production line or something, saying the rest would arrive in due course, and put that in their stockings with the few we could rake up. However when the arrival of the remainder coincided rather closely with the arrival of my luggage, DGC aged 9 & 7 soon sussed it. Somewhat to my relief I must say, as I thought that it was high time they knew the truth!
Like so many issues, I don't think there's a right answer, there are different approaches and each of us makes our choice. Which is well illustrated in the postings on this issue!