The debut of thundering supergroup Audioslave--featuring members of Rage Against the Machine post-Zack de la Rocha with ex-Soundgarden singer Chris Cornell--is as much curio as fascinating blend of visions. Cornell might be outnumbered, but his unmistakable holler and nihilistic imagery ensure that Audioslave, the album, recalls early Soundgarden. That's especially true since de la Rocha took Rage's signature rap and politicking with him. Still, if...