I was never the hugest Soundgarden fan but this is certainly sad. His vocals on Say Hello to Heaven (TotD) are chilling.
There's a doc called Hype! from a few years back chronicling the early Seattle/grunge scene and they show a Soundgarden concert and, I wish I could remember the name of the song, they sounded even better live than on the records. He did have some voice, rip.