[paulmd]

This also varies by the target audience.

Stuff that is released via publically-tracked torrent (i.e. for mass-market audiences) often targets around 1.5-2 GB for a feature-length movie in 1080p. In contrast, releases aimed at Usenet (the technical crowd) are often 6-7 GB and sometimes as large as 11-13 GB for the same movie.

On the other hand the situation is much more equitable for audio. Lossless audio torrents are pretty common even in the torrent world, and due to the typically greater number of torrents available the overall selection of lossless files is probably at least as large as on Usenet.

I would assume that private trackers tend towards higher-quality releases.