These days, newly crowned octogenarian B.B. King seems less an archetypal grizzled bluesman than a wise old Zen master, at peace with the world and himself. That doesn't mean he can't still sing and play some mean blues. He does it again on this winning duets CD, 80, collaborating with acolytes like Eric Clapton, Van Morrison, Sheryl Crow, and others. Nicest left-field surprise: the team-up with Elton John on the rollicking ''Rock This House.''