Judging how much television is best for your family requires a look at your family. For other families, TV watching is unlimited, as long as program choice is educational or family-oriented. The best answer for your family may be something else entirely. Look at television in the context of everything else your family does. Look particularly at your children's lives.
Television is a non-physical activity.
If so, you may want to omit TV time, and some other nonphysical activities and encourage active family time daily. Taking a walk with your child may easily be valued far more highly than an afternoon of cartoons or an evening of computer games. Television could be relegated to weekend mornings before more active pursuits. For active kids, on the other hand, television may be a way of relaxing - calming down from all the frenzied activity of the day. For that child, an hour or even more of television may offer the kind of relaxation needed to ensure a good night's sleep.