I guess this is why 1080i/p looks better on my Pioneer 151 60" than movies from Apple TV. Though on a 37" Panasonic plasma Apple TV looks not bad.
Something people also forget is that the 720/1080 i/p business is a tiny part of the overall picture quality - most stuff is heavily compressed.
Compare HDCAM SR's data rate of 440Mbps with the data rate of something in HD from Apple TV. From memory a 40min SR tape holds well over 100GB.