Wow, you go to church before pressies, Heald!? I admire that. I can usually barely wait mum's obligatory coffee+toast time before opening ours.
After pressie opening, we get dressed (yes, very lazy family), have more breakfast and then mosey gently around until it's time for dinner wherever we're going that year. Then we pig out on scrummy crimbo grub (mostly turkey/chicken/MANY roast potatoes = my favourite), drink lots of booze and play charades if we're at my aunt's house.