That delightful editorial from the New York Sun in 1895 made a warm and fuzzy case for belief in Santa Claus. In my own childhood home, since I was four years older than my sister, I encouraged her belief as long as possible so we could get more presents at Christmas. Now we have a poll showing that Americans see a decline in belief in Santa Claus but still value it as a tradition and contribution to imagination.
By the way, I have been persuaded by recent research that Clement Moore did not write the famous "Visit from St. Nicholas" poem, as discussed here. But, of course, I could be wrong.