By the way, other than have theTV drop off iTunes on the rare occasion (simply restart iTunes to correct and haven't has an incidents since latest iTunes/OS X updates)
So where is your library stored? On a computer or server that is always on, in addition to all these components?
Can Apple TV see content on a remote hard drive, say a NAS drive served off an Airport Extreme, or is it reliant upon iTunes running on a computer someplace?