Popular actor-talk host Jon Stewart is -- according to columnist Liz Smith -- maturing into one of his generation's best anchormen and personalities. Stewart, whose "The Daily Show" has won the Peabody Award, tells Smith that he's just one bad show away from being a night manager at a restaurant. Asked about his movie experiences, he noted that his movies are "very big in Belgium . . . South America, very popular down there." He says the best thing about getting a Peabody is the free lunch that comes with it. Stewart is profiled in the latest issue of Vanity Fair and will soon be the subject of a major segment on "60 Minutes."