I think the traditions that I remember the most as a child, and the ones my kiddos remember, too, are the simple ones. The let's-just-be-together ones.
A few Christmas's ago I bought a book filled with Christmas stories like "Twas the Night before Christmas" "The Nutcracker" and "The Drummer Boy." I think there are over 30 of them in there! When I bought the book we started the tradition of reading one (or several!) of the stories by the lit up tree, with lots of candle light, and homemade cocoa. It's such a sweet quiet time and I love it! We usually do this several times through the season.