Sick of Hollywood’s standard superhero fare? You could do worse than to take in “J. Edgar,” the new Clint Eastwood-directed biopic about the legendary FBI director who served eight presidents over nearly five decades. “Served” isn’t quite right–Hoover mainly served himself, and the dossiers he compiled through his agency’s spying on top political figures made presidents fear to replace him, lest he, as Richard Nixon put it, “pull down the temple” in retaliation.