Play It Loud: The Story of Marshall

While it's a great summary and there's some well known figures, it would have been great to see more instead of excerpts from old interviews (like an Angus Young, Jimmy Page, Ritchie Blackmore etc interview).

But there's some great insight from Pete Townshend, John Lord, Slash amoung others. I think it's worth it just to listen to Lemmy.

The doco briefly outlined their major models (like JTM45, JTM100 and JCM800), but there's a lot more models used (like the bluesbreaker, major 200 etc). And could have said something about their failures (like the 8x12).

One other thing which they never really touched on (which was probably nearly as important as the amp) was their speaker of choice - Celestion. This is a huge part of the sounds and what gave the amp the character too.