We tend to rent or borrow vacation homes when we visit a location for more than a weekend and, with two kids, our stuff quickly spreads into every nook and cranny. From experience, I know that whatever we accidentally leave behind ends up being the thing a kid uncontrollably desires on the way home.
Here's how I make sure nothing gets forgotten when we pack up to leave:
First, I put the kids in front of the TV. Nothing else keeps them in one spot like the television.
Next, I turn on every room light. Once all the lights are on, I do a thorough room-by-room search for a stuff.
When a room is clear, I turn out the light and close the door.
Once all the lights are out and doors are closed, I know I've hit every space. Now, if something doesn't make it home with us, it wasn't for a lack of trying.
If your kids are old enough, I would add a step before the room-by-room inspection: have them pack their suitcases, or at least gather their stuff into a single corner. My motto: "always better when several brains work on a problem."
Do you have a system for packing up at the end of a vacation?