And now, ladies and gentlemen, we officially enter the golden age of ''The Simpsons'',which extended from seasons 3 through 8. Gone is (most of) the ragtag animation, slower pacing, and vocal experimentation of the first two years, and in are some of the series' most memorable (and ambitious) episodes. Complete with nine major-league-baseball guest stars, ''Homer at the Bat'' remains the season's true pitch-perfect outing, while Sideshow Bob makes another killer appearance in ''Black Widower,'' and happiness is always just a ''Flaming Moe's'' away. As usual, the main meat (mmm...meat) of the extras comes courtesy of the 24 commentary tracks. Cast and crew recall a table read with Michael Jackson for ''Stark Raving Dad,'' and periodically provide a few notes on the stars they couldn't get (Bruce Springsteen turned down Sting's role in ''Radio Bart'' and the part of Fat Tony was originally offered to Sheldon Leonard). Plus, when is it not funny to hear people dis Jose Canseco? Never.