As usual, Terry Gilliam makes the viewer see his films in a whole new light after he provides his commentary. My favorite commentator (and filmmaker) to date, I gained a whole new appreciation for this movie when I learned Gilliam's input. Like with many of his films, he leaves a lot of plot points in the film ambiguously unresolved, to let the viewer analyze and decide for themselves what they're about (one example from this film is the markings on Heath Ledger's forehead near the beginning of the film, which Gilliam himself said he's still not sure what they mean). He also shoots down critics and naysayers who said that Ledger couldn't keep a British accent, when in fact he could perfectly, but he decided to make his character more chameleon-like by alternating between American, British and Australian accents throughout the film. But the best part of the commentary is Gilliam talking about the script and film changes that occurred as a result of Ledger's tragic death. My favorite was how the 3 actors that replaced Ledger for the Imaginarium scenes played off Ledger's aforementioned chameleon-like ways by their casting: we have Johnny Depp (American), Jude Law (British) and Colin Farrell (Australian). Gilliam makes fanboys happy by comparing some of the Imaginarium scenes to his old animations from his days working with Monty Python. All in all, if you like this film, Terry Gilliam, or anything related to this, the commentary is a must-listen. The viewer owes it to themselves.

Very good as always from Gilliam. He knows people are listening and gets to speak his mind and explain things from his side. Like a one sided interview. He covers a wide range of topics about the film from concepts to shoots.
I wanted to add to the previous review above, Colin Farrell - Irish. Not Australian.

Just listened to Giliam's rant over the credits roll. That's where he really comes alive for some reason. Also a little of his craziness comes through. The speech about 'We are the world', Hilarious. Thats worth a listen right there.

An excellent commentary in that it made me appreciate the film much more. I thought I understood what was going on when I saw it in the theater, but I did not in many scenes. And Gilliam also points out little details all around the edges, which his films always have.

There is of course a lengthy discussion about Ledger dying, and the three actors taking over for him. But he is still rather funny through most of it. And lots of stuff about the difficulties of finishing the film, much less making it.

Definitely worth listening to after having seen the film.