Just to be clear, when you say hi-def movies from Apple are you saying 720p or 1080p? Blu-Ray and HD-DVD are 1080p. If you have the rig that's the way to go. But 1080p is still high end most HDTV sets are either 720p or 1080i.
I could see Apple doing 720p movies since the AppleTV is capable of doing that, but they would have to come out with a whole new unit with 1080p abilities and a larger hard drive to compete with Blu-Ray and HD-DVD. I don't see that happening for at least two years.