Chuck Schuldiner
Awesome singer/guitarist virtuoso who pioneered death metal.  Possessed didn't!  Chuck died of a brain tumor in 2001.  It was metal's greatest tragedy yet, maybe tying with Dimebag's death in '04.
R.I.P. Chuck Schuldiner.  Somewhere up in heaven, or somewhere down in the pits of hell, you're looking down, or, uh, up, at all of us faithful death metalhead mourners.