That's pretty good use of transferrence! Of course Santa is not a necessary component of the "spirit of giving". Nicholas of Nicea was nothing to admire, so your mention of St. Nicholas does get closer to the point. But the real point is that I want my boy to be a Christian, so the last thing I want to do is sit him down and explain, "Remember the nice invisble man who watches over you and gives you things? Well, really he's just made up."
True enough. Presents are also not a necessary component of "the spirit of giving". Nor is the Christmas tree required, nor decorations, nor feasting, nor nativity scenes. Gosh, am I still transferring?? Have a very intellectually honest, St. Nicholas bashing, symbolically devoid (but inwardly merry) Christmas. And Happy New Year (or is Old Man Time a downer too).
His cult in the Greek Church is old and especially popular in Russia. As early as the sixth century Emperor Justinian I built a church in his honour at Constantinople, and his name occurs in the liturgy ascribed to St. Chrysostom. In Italy his cult seems to have begun with the translation of his relics to Bari, but in Germany it began already under Otto II, probably because his wife Theophano was a Grecian. Bishop Reginald of Eichstaedt (d. 991) is known to have written a metric, "Vita S. Nicholai."
The course of centuries has not lessened his popularity. The following places honour him as patron: Greece, Russia, the Kingdom of Naples, Sicily, Lorraine, the Diocese of Liège; many cities in Italy, Germany, Austria, and Belgium; Campen in the Netherlands; Corfu in Greece; Freiburg in Switzerland; and Moscow in Russia. He is patron of mariners, merchants, bakers, travellers, children, etc. His representations in art are as various as his alleged miracles.
In Germany, Switzerland, and the Netherlands, they have the custom of making him the secret purveyor of gifts to children on 6 December, the day on which the Church celebrates his feast; in the United States and some other countries St. Nicholas has become identified with Santa Claus who distributes gifts to children on Christmas eve.
His relics are still preserved in the church of San Nicola in Bari; up to the present day an oily substance, known as Manna di S. Nicola, which is highly valued for its medicinal powers, is said to flow from them."
from the Catholic Encyclopedia