The good is shrinking or barely holding its own, the bad and the ugly proliferate with amazing speed. Television is a cesspool with a few non-polluted islands.
Television is good for coverage of breaking news. I know no one who is old enough and owns a TV set who did not watch coverage of 911. Images of birds in the Gulf of Mexico covered with oil, still trying to move have impact in a way that even the most amazing still shots don't - one blink that signals a still beating heart says it all.
Television is good for live coverage of sports events - the Olympics, Stanley Cup, World Cup, Superbowl. Watching the play unfold and not knowing who will win is exciting. Radio just isn't the same.
Beyond that, it gets dicier. Reality shows ARE television to many, and they attract millions of viewers. Mostly, I don't care for them. Many are some form of competition. Many show people at their worst. All are voyeurism in a way that is worse than that in movies and fictional programs. Not only is much of the content idiotic, watching all that greed, naked ambition, and nastiness isn't much fun.
I refuse to watch any reality show with children - they have no say, no informed consent. Who wants to have the potty training episode turn up at the wrong moment in the future? Much worse - the fact of being on the show must shape the very essence of the childhood experience and can't help but give a child a somewhat skewed idea of his or her relationship with others.
Sitcoms insult the intelligence, most of them anyway. Dramas can have good storylines, backstory, and characters, but overwhelm us with the very most degraded aspects of human life. I don't want to spend any of my precious time watching endless twists on rape, murder, torturers, and serial killers; it's enough to stay informed about all the madness in real life.
Selectivity is the key. And the mute button, don't forget the mute button.