Have to admit I don't really have any long standing traditions yet, as I didn't particularly like Xmas when I was a child. Apart from the orange and lemon slice jelly sweet things, gotta have them, and as the only child I was always allowed the special round sweet in the middle of the packet :o
So many of our new traditions that we are slowly building up (DC are 4 and 2 now) are shamelessly nicked from MN!
We always get the DCs a new Xmas tree decoration, so that when they grow up they have lots of special ones (although I need to replace DD's from last year, a lovely fairy which broke). These and some new jammies get delivered outside the front door by the elves on Xmas eve. I'm thinking of also including a new book to read at bedtime that night?
Last year we also decided that because we (as in DH and I) like so much of the same stuff, we would invest some of our budget in a joint present instead of risking buying the same thing for each other. Last year it was a couple of DVD box sets, this year it is a board game we've been tracking down for years. We also agreed that Xmas presents will always include board games to play on the day.
Can't think of much else really - Xmas itself is fairly low key here. Since having DCs we've had the day just for us, and family come over on 24th/26th. We are good cooks so my parents buy us the food :o DH's older 3 DCs always spend Xmas with their mum so we have another day for them around new year too. The 25th is pretty much just dossing around playing with the presents.