Although not yet released, the existence of Microsoft's Xbox 360 Arcade package has been confirmed. The unit has been rumored to replace the Core model. Photographs confirm the $279.99 price point, and indicate that the games Boom-Boom Rocket, Pac-man, Uno, Feeding Frenzy, and Luxor 2 are indeed included on a compilation disc. Like the Core, the Arcade model comes without hard drive, but includes 256MB memory card, wireless controller, and HDMI port. The reason given for this early stock availability is human error - incorrect shipping date.
Source: Engadget