This year I banked $125 a fortnight into my Christmas account. Next year I am banking $50 as I want to build up an emergency/rainy day account as well. I love my Christmas account!
I'm thinking of putting $100 a month into it plus grocery gift cards bought throughout the year. We've already got money that is on a automatic savings plan so don't really want to push it.
I think the Christmas accounts are such a good idea. A shame not many banks do it though.