Last year we hid them in the office. Which has now been converted to DDs bedroom. This year I'm hiding them in the living room! We have a bar area (filled with books don't get crazy) that has a large cabinet and the kids aren't allowed in there- that's where they're going!
we usually dont have much money to spend on presents so I will wrap a few and put them under the tree before Christmas but I will wrap a majority on Christmas Eve.
I usually do them all at once, or as many as I can get done in whatever time I have. This year we have an extra closet in our room that we just use for storage so we will stash them there.