The new version appears to have 4GB of built in storage – far more than the present model's 256MB capacity. Other items included in the deal, such as software and extra peripherals, have not been revealed. For what it's worth, the existing package ships with two games and one controller.
The updated offering is priced at €148.99, or about $190 in U.S. dollars. That's in line with the current €149.99 charge for an Xbox 360 Arcade in Germany, so it is likely that this unit will serve as a direct replacement of today's budget option.