ZZ Top: Rhythmeen

JUST WHEN THE TOP WERE sounding like they'd run out of juice a mere 26 years into their career, they pull out a plum. Could it be that as they push 50, the trio are at last growing into their long-cultivated image of gnarled and barnacled dissipation? Like the Stones in reverse, the further time's winged chariot has conveyed them from fresh-faced youth, the more convincing they've become.