There is another alternative that doesn't necessitate you investing in any more space. If you have more than one Mac in the house, synch your AppleTV to the Mac with a smaller library, and then just stream all the content from your primary machine. Practically, I can't say I've tried to stream HD movies from another machine in the network, but music certainly works without a hitch. Perhaps someone else can speak to experience of streaming movies not actually on the AppleTV HD. I've got to assume most of what you have is movies and TV, as that would be a heck of a lot of music!