Just curious really!
As a child our Xmas mornings were of the frenzied kind (in a good way)-we all went downstairs to check 'he'd' been, then dived into our piles of presents all at the same time (us three children I mean).
We've pretty much done the same with my kids, which is sometimes difficult keeping tabs on who bought what, but generally feels nice as it's how I've always done.
STBXH's family are the 'one-at-a-time and everyone watch' variety, and I know of others who wait until after breakfast or after lunch.
Which type are you (and if it's the latter, how on earth do you contain the kids and get them to wait with a massive pile of pressies-mine would be too distracted to eat I think!)?