...that you can use your own External Hard Drive with it!
That's right, if you don't know already, you can use a USB external hard drive (formatted to FAT32) on your Xbox 360!
I've ran out of room on my 160GB Hard Drive that's actually attached to my Xbox already, so I just simply hooked up my external.
I hooked up a 20GB (easier to format to FAT32, IMO) external, and left the 160GB attached to my machine. Now, I just transferred all my game saves and Xbox/gaming-related data to the 20GB, and left Movies, Music, photos, etc on the 160GB. Perfect setup!!
Any hard drive that is formatted to FAT32 and is USB will work.
Figured others, like me with this problem, could use this tip, so I posed it here.