S&MAmazon. com At a point in their career when most bands would rest their laurels upon a greatest hits package or live album, Metallica has done both, but with a decidedly loopy twist. They've recorded a double live greatest hits package with the San Francisco Symphony Orchestra "sitting in." Rock history and cutout bins are littered with previous attempts at a rock symphonic fusion, from Emerson, Lake & Palmer to Deep Purple to the Moody Blues and the