The next update for Xbox 360 will allow the use of 2TB hard drives to store Xbox 360 data. The next update for Xbox 360 Preview Program members will allow the use of 2TB hard drives to store Xbox 360 data.

If you are not part of the Preview program you will get this functionality later this year. In addition we will also no longer reserve space in advance on your hard drive. If you are using 16GB of hard drive space for games - we will only take 16GB of space. And just like today - you will be able to use two external drives at a time. 

Note: Some drives may be incompatible or have performance issues. If you already have space reserved for storing Xbox 360 data, you will need to clear the Xbox 360 storage to gain full access to the drive. If you are in the Preview program, please review the list of known issues before formatting your drive.

Xbox 360 Getting 2 TB Hard Drive Support