It was the Soundgarden 1994 release Superunknown that catapulted the group into superstardom, but it was 1991's Badmotorfinger in which the group found their sound. This video was filmed 2 years before Superunknown, back when Soundgarden could still legitimately be called "Seattle's best kept secret" (except for the Melvins, but that's another review).
Taken from a performance at the Paramount Theater in Seattle, this video shows the boys in prime form. Matt Cameron is just about the best modern rock drummer there is, providing the rumble that allows Kim Thayil (and occasionally singer Chris Cornell) to lay the Heaviest guitars this side of the Misty Mountains.
If you aren't already into Soundgarden, I wouldn't recommend watching this movie first. Buy Badmotorfinger, listen to it, and then watch this. The "Black Hole" Soundgarden fan may tend to find this video dragging on at times.
True fans of the band, or anyone who caught them in the early 90's will enjoy this trip down memory lane.