The most interesting part for me, though, was the Peter Saville gallery, which consisted of stills of various posters and album/single covers, with Saville and Wilson's overdubbed dialogue. It goes for about 50 minutes, and they spend a small but noticeable proportion of that time arguing, from debating the significance of the lateness of the FAC1 poster (Saville saying it wasn't as bad as in the film, and Wilson pointing out that it was more late than it was there) to apportioning the blame for Factory making a loss on the overdesigned Blue Monday single. In between that, Saville manages to talk quite a bit about the aesthetic theories behind various design decisions, the exact origins of the Joy Division Closer cover image and the ironic benefits of out-of-touch photo libraries.
I'll probably watch disc 1 at some stage soon, at least with the commentary. Or with a friend who hasn't seen it; I've seen the film twice already.