As blockbuster trades go, the Drive-By Truckers' swapping of Jason Isbell for steel guitarist John Neff, plus an enhanced role for bassist Shonna Tucker, ranks with dealing Lou Brock for Ernie Broglio. But the move was inevitable, as few bands have ever sustained the creative and economic push and pull of three virtuoso songwriters. The secret to the Drive-By Truckers' success isn't its Southern-rock pride, but rather the furious power of their individualistic songwriting. If nothing else, last year's overlong Brighter Than Creation's Dark tested the band's reserves of narrative, character and conflict. From Patterson Hood's withering Oedipal drama "Daddy Needs a Drink" to Michael Cooley's decadent teenage Polaroid "3 Dimes Down," the Truckers have found just how deep the parallel currents of country pathos and rock & roll realism can be.