Microsoft seems to be rewarding people who buy pre-order Xbox One. First off, if you pre-order your console from any retailer, you will be getting a limited Xbox One Day One Edition which includes a commemorative engraved controller.
Also, if you buy the console from Xbox 360’s dashboard, you will unlock a special 0G achievement for “ensuring that the most powerful console ever made will be delivered to you on day one”. If you buy the console using the dashboard, you will get it directly from Microsoft’s store on launch day. Xbox One will be available in November for $499.