From Xbox Website

Xbox happens to have 3 360 models: "Arcade", "Premium" and "Elite". These vary in specification and gameplay.

• "The Xbox 360 Arcade System is everything you need to start playing. With a Wireless Controller, 256MB Memory Unit, Xbox LIVE Silver Membership and 5 Arcade Games, there’s never been a better time to jump in. Go play!"
• "If you're a serious gamer looking for the ultimate console, the search ends here. Fully loaded, it's the unsurpassed gaming and entertainment experience right out of the box."
• Introducing Xbox 360™ Elite, the premier Xbox 360 console package that includes a massive 120GB hard drive, a HDMI port, and HDMI cable, all wrapped up with a premium black finish. Xbox 360 Elite also includes a black wireless controller and black Xbox LIVE® headset. Xbox 360 Elite has enough space for a whole library of Xbox LIVE Arcade games as well as downloadable high-definition TV shows, movies, music, and all the other content available from Xbox LIVE Marketplace.

As you can see the Elite is the main rival to Sony's PS3. And Microsofts marketing techniques are very similar to that of Sony.