It isn't Christmas for me without the traditional tree-arguement. DH always says this year he is putting his foot down and we are gettign an articial tree. I huff and then show him the price of the only artificial tree that I would even consider. He relents but says that he will be buying artificial tree in January sales, so this is last real tree ever (he has been threatening this for years, but I always ensure we are suitably skint in January so that this is not an option, while at the time nodding in reluctant agreement 
) WE then go to pick the tree. He points out some 2ft dwarf conifer. I pick out a specimen that wouldn't look out of place in Times Square. WE battle it out and eventually come home barely speaking with a tree that he thinks is too big and I think is too small, and all the kids moan about pine needles down the back of their necks on the way home. When we get home, said tree never ever ever fits in silly stand, and Dh has to drag it back out cursing and grumbling to saw bits off the bottom. I then accuse him of sawing off too much and butchering tree. Once it goes up, I stand teary-eyed and emotional, and he grudgingly admits it looks good- but still too big!
I do the thing where the kids get to choose a decoration each each year. But I never throw any of them away, so each year my tree gets more and more cluttered, and it takes me hours to unwrap and reminisce over each and every decoration, even the cheapo crappy ones which were all I could afford my first Christmas away from home.
I also do the new PJs, and always read the dc "The Night Before Christmas" on Christmas Eve. We also do the magic dust for the reindeer, the carrot for Rudolph (which DH has to take a reindeer-sized bite out of!) and the sherry for Santa (that's my job to see that off!)
Once the kids are in bed, we adults (DH, my dad and I) stay up wrapping and assembling, over a couple of glasses of Bailey's/ wine. Then at midnight we open our pressies to each other. This was a tradition started my parents, and means we can focus purely on the kids on Christmas morning, and actually pay attention to the pressies we get from each other without all the hullaballoo and without having to insert batteries/ detach that wire that seems necessary to hold toys in packaging in between unwrapping.
I take the kids to church after the present unwrapping (which is first thing- could never understand how folk can make small children wait like that!), where they do a nice children's mass and where they usually see their friends, As a bonus by the time I come back DH has usually tidied up and had the dogs out.
I like the day to be relaxed- no specific timings, plenty of time between courses if people want it, usually end up with coffee and chocs at around 9pm! Also like to fit in plenty of champers/ wine between times. Once kids are in bed, and guests gone, like to settle down with Royle family or similar, although sometimes have neighbours/ rellies drop in for triv/ pictionary and recycle the cheese and biscuits etc!
L love Christmas, and always want the day to last as long as possible!