The premium package includes an Xbox 360, a detachable 20-GB hard-drive, a wireless controller, faceplate, headset, a component HD AV cable, an Ethernet cable, and for a limited time, a remote controller.
The Core 360 System is stripped down in comparison. It includes an Xbox 360, one standard wired controller, a faceplate, and a standard AV cable. The $399 package is designed for the high-definition gaming era; the other is designed for a no-frills, current-gen set-up. Presumably both systems come with power cords, though Microsoft's press releases didn't actually include them.
Asian customers will have to wait till the Tokyo Game Show in mid-September to find out what is happening for them. Still no real word on a release date, but the smart money is on November for the North American and European launch.