We have it in the early evening. I love this tradition. It means no one is getting up at crack of dawn to sort out the turkey, no one has the stress of feeling like they should be in two places at once- prepping veg and helping DC set up their new presents.
We wake up, do stockings together over coffee, then have bucks fizz and bagels with smoked salmon and scrambled egg. Then we get dressed and do presents under the tree. After that, go for a walk or if the weather is foul we just chill - reading new books, listening to new CD's, building new Lego, trying on new clothes etc. If people are hungry, there is home made soup, a good cheese board, Christmas cake, mince pies, yule log for a light lunch. After that, I start prepping dinner. DS1 starts laying the table, we listen to carols, watch a family film while the turkey is cooking, or play games.
Then have drinks before dinner, traditional roast - no starter. Pause to do some Christmas quizzes and silly games we make up every year. Then flaming pudding. Chat, slope off to have long baths, read some more and off to bed.
DC are adults now, though. And we go to midnight mass on Christmas Eve so don't usually attend church on the day.
When they were younger, still the same, but more focus on playing with their new toys and a frosty walk to work off too much excitement. We also staggered the present opening through the day a bit.