What additional hard drive do you use for your xbox?
And what is game sharing?
I prefer the western digital my passport 2tb.
I picked it because its small, USB powered, big, and cheap
game sharing is when you and a friend swap accounts, set each other accounts as the home xbox then re-log in as your account. This gives you access to each other's digital library. It also allows me and my buddy to technically only pay $30 a game because we split it.