For the first time ever, GameStop is doing a downloadable content pre-order campaign and they're kicking things off with Halo: Reach. Simply pre-order the "Noble Map pack" from GameStop and you'll get yourself a Mark V SPARTAN Flaming Helmet ... for your Avatar.
I get pre-ordering games as it helps a store know how many copies they should get of a particular title and it tells the publisher/developer what kind of pre-launch demand there is for their game. But for DLC? Seriously? That makes no sense. It's not like Microsoft is going to run out of codes or anything.