If you preorder an Xbox One console, you'll get hold of an Xbox One Day One bundle, rather than the standard edition.
The Day One bundle includes limited edition packaging, as well a specially marked controller, a limited Xbox One Day One achievement and most interestingly of all, what appears to be a free 12-month Xbox Live subscription. Which, we guess, would knock about $40 off the asking price. Theoretically.
No, we're not clutching at straws. Honest.
Microsoft has released some packshots, which show what you'll be getting on day one.
[13/06/2013] - Update: We are seeking clarification as to whether the 12-month Xbox Live Gold subscription is free with Day One preorders, or whether it will be AVAILABLE on Day One.
[13/06/2013] - Update: We have made a grave error. The initial text we were given suggested that Xbox Live was free for 12-months with the "Day One" preorder pack. That is in fact not correct. The "Day One" Xbox Live 12-month Gold subscription will be available as a separate purchase. We're sorry for any confusion.