I make up a bowl of fresh fruit on Christmas Eve, so all I have to do is spoon it out on 25th. Diced apple, orange segments, berries etc. It's nice with plain yoghurt or on its own.
We squeeze oranges - although sometimes we buy a bottle of freshly squeezed juice on 24th.
We make a large cafetiere of coffee, and usually refill it!!
We either make Jus-Rol pastries (generally croissants, sometimes cinnamon rolls - just need rolling/slicing and brushing on some milk or beaten egg for shine) or M&S pastries (pain au raisin, pain au chocolat or croissants - which need NO work) - throw them in the oven for the appropriate length of time while stockings are checked, kettle boiled for coffee, table set etc...and they're done at the perfect time!
We have occasionally had some bacon sandwiches, or scrambled eggs with smoked salmon, but we have so much to eat later, and so much relatively rich food, that a nice but lighter breakfast suits us. There's always plenty to snack on if we do get peckish before other meals anyway! 