* When I originally reviewed The Last Waltz, I called it the best rock movie I'd seen, and it still holds the title. Martin Scorsese's elegant camera choreography is an ideal complement for surprisingly sturdy music by the Band and various guests, including the ever-surprising Bob Dylan. Now ''The Last Waltz'' is being revived in New York, to show off a new stereo-sound system at the Sutton Theater. It will soon move over to the Beekman, another comfortable East Side showplace, and there's active talk of a national revival for the film, concentrating on movie houses with excellent acoustical setups. ''The Last Waltz'' has clearly not had its last waltz yet.