Token Black Guy

On the theme of the representation of blacks in American television (and movies), I'd like to bring up the topic of the "token" black character: a black person inserted into an otherwise white cast primarily or strictly to show diversity, but who is otherwise unimportant, superfluous, or even stereotypical. More discussion of the "token black" character may be found here.

Above is an image of "Token Black," (his name) the self-consciously "token" black character from the South Park television series. In the spirit of South Park parody, Token actually defies many "black" stereotypes: he is intelligent, speaks in conventional American English (rather than some version of "black dialect"), comes from a wealthy, professional family, and otherwise fails to draw attention to his race.

My discussion question: are such "token" black characters, and other "token" representation of black in the media, helpful or harmful towards cultural integration? Is it better to throw in a black character and have him or her constantly exhibit stereotypes of his or her race, or to eliminate such characters and return to white-dominated movies and television shows? Clearly, a human (rather than contrived) depiction of African-Americans is preferable to both alternatives; but given one or the other, which is better?