I highly recommend this documentary for any punk rock fans, or fans of music history in general. Even if you don't like punk rock music, there is a lot to be learned from this film. This movie does a pretty good job of summing up why these people were making the music they were making, starting in the mid-60's, going through roughly 1980 in detail. The film includes interviews with many people who either made the music (New York Dolls, Suicide, The Damned, The Clash, Sex Pistols, The Ramones, Siouxsie and the Banshees, Buzzcocks, and more...well, the members still alive who would agree to interviews, at least), and people who made music that was influenced by the first wave of punk rock (Henry Rollins, Jello Biafra, Thurston Moore, Agnostic Front).
What is "punk rock"? That seems to be the mission statement of the film. How do you define a style that bases itself in the idea of non-conformity? One of the most interesting things to learn from the film is that many of the bands who made the music in the late `70's seem to believe that punk died when bands started referring to themselves as "punk".
The film does have a few faults. There are some glaringly missing interviews. From the pre/proto-punk era, they did manage to get a brief clip of John Cale from The Velvet Underground, and members of MC5, but not one member of The Stooges? Without a lot of interviews from the pre/proto era, that part of the film plays a little like one of those VH1 shows, where they show a clip of something nostalgic, and then a famous person comes on and says something like, "I remember that. I like that." Fortunately, there isn't too much of that, though.
Another problem with the film is the glaring omission of the 80's. The film has members of Black Flag, Bad Brains, and the Dead Kennedys in the movie, and yet sticks to the premise that "punk died in the 80's and nothing happened until Nirvana". This is a poor statement to make, for two reasons. First, when they say that punk died in 1980, many of the band members come off like those aging hippies who wag their fingers at kids and say, "music hasn't been the same since the Beatles". Maybe this is because I lived in California, where in the 80's punk and skate culture went hand in hand, but off the top of my head I can think of Bad Religion, Social Distortion, Circle Jerks, D.O.A., Agent Orange, Descendents, Millions of Dead Cops, Subhumans, D.R.I., T.S.O.L., Minutemen, Suicidal Tendencies, Husker Du, Flipper, JFA, Dead Milkmen, DI, Drunk Injuns, and many more. Punk was alive and thriving, as far as I could tell. It just wasn't like the days when bands like The Clash and The Sex Pistols appeared on the record charts (which may have been a good thing).
Also, lightly touched on, was the 90's generation of punk. Think what you will about the pre-pop-punk like Pennywise, Vandals, Offspring, Green Day, Rancid, Dropkick Murphys, Swingin' Utters, NOFX, etc., like it or not, those bands are part of the "punk" legacy. Why would the movie mention Korn and Limp Biscuit, but not most of those bands? Fortunately the documentary does make the distinction between those bands, and bands like Blink182, Good Charlotte, and A Simple Plan, who represent the complete assimilation of punk into "the system", the true death of punk.
Well, shortcomings and all, this is still a wonderful movie that will provide you with a knowledgeable history of early punk rock. To fill in some of the blanks, I recommend seeing the movies "American Hardcore", "The End of the Century", "The Filth and the Fury", "Westway to the World", "We Jam Econo", "Repo Man", and "Devo - The Complete Truth About De-Evolution".
EDIT: For a complete punk history, do yourself a favor and watch "Punk Attitude" (~mid-sixties - 1981), "American Hardcore" (~1979-1986), and "Punk's Not Dead" (~1986-present). These three movies have come out in succession, all made by different directors. Yet, as luck would have it, they pretty much cover the span of punk history up to 2007. Also, some time in the next year (I'm writing this in 2007), "The Decline of Western Civilization" will finally be released on DVD.