Wilco's seventh studio album is a triumph of determined simplicity by a band that has been running from the obvious for most of this decade. The title is the giveaway. So is the opening gag, "Wilco (The Song)," with its rattling-bones guitar and singer-boss Jeff Tweedy's assurance, sung like pillow talk, that his combo is good for all that ails you: "Do you dabble in depression?/Is someone twistin...