I'm thinking about getting my first Apple TV but am pretty unfamiliar with how it all works. I have tons of iTunes music and movies on my iMac that I want to be able to play through my speakers connected to my TV/sound system. I also want to be able to play movies from my iMac on my TV. Does this require an Apple TV? Will I have to have the content on the actual Apple TV device? Or will I be able to "stream" it from my iMac through the Apple TV? I don't think I'll need the 64GB version if I am able to store everything on my iMac. What exactly would I need that much space for on the device itself? I'd appreciate any input on how all of this works.