I was just thinking with so many people that collect different aspects of video games (carts, magazines, arcades, action figures etc.) maybe there are people out there who collect pre-order bonuses or who will eventually go onto to collecting them. Lets rattle off some titles and see how many games have come with something by pre-ordering (a demo of the game you are buying doesn't count).

Castlevania: Portrait of Ruin- bonus CD, stylus, art book, timeline poster
Mario Galaxy: The Mario Galaxy coin.