I'm not even a huge fan of Sepultura on record. I tend more towards Kreator/Forbidden/Testament/Laaz Rockit for thrash. But this is so furious I watch it all the time. I would cite Live After Death and Double Live Assassins as equally great live recordings in terms of energy, but this rules the angry side of the spectrum with an iron fist. Every single instrument just sounds pissed. Even more impressive because most extreme metal bands don't translate well to live albums/DVDs well at all.
[VIDEO]http://www.youtube.com/watch?v=3lw4r4dFS2U]Sepultura Under Siege Live Barcelona 1991 - YouTube[/VIDEO]