Interesting views. So, we 'on the continent' are obviously completely miserable gits, as many countries here simply don't 'do' Santa, like they do in the UK. The dutch have St. Nik on the 6th, my PILs do the "Christkind" (Christ child brings presents on the 24th), some just get presents, ... Oddly enough all the kids here still get really excited, they adore baking Christmas biscuits, decorating the tree, opening the Advents calendar, singing carols, visiting the Christmas markets, ... and their eyes light up when they finally see the presents under the tree. For me the build up to Christmas makes the magic.
DS1 is now 3.5y and he's sussed that it's all something to do with presents, and I don't think he currently cares where they come from. I'll stick with the line that we're celebrating Jesus' birthday, as that's true and he understands the concept of birthdays and presents. My DH ensured that St. Nik. put something in his shoes on the 6th of Dec. (we live on the border to the Netherlands). The PILs will tell him something about the "Christkind", he's also going to get a few presents on the 25th ... it's all good.
I find it a little sad, that on MN if you don't stick to the Santa dogma, then you are often considered a miserable, or mean parent, sucking the magic out of your kids lives.
And if a slightly chubby, pasty, underdressed kid with a blinking Santa hat (that's how we pick the UK visitors 
) comes up to me at the local Christmas market and asks me if Santa is real, then I'll ask him/her what he/she thinks, and then say, well I think then that's ok. No lying required.