I just installed the Apple TV and I've got mine running all the time. I've found that the Apple TV sounds much better if you sync your iTunes library to the Apple TV drive rather than stream it. Syncing also gives you the ability to personalize the photo screen saver which is very cool. Now, back to topic, if you are going to sync the Apple TV than you would want to leave it on all the time so it will sync automatically when you open itunes as opposed to manually turning it on each time. Just my .02