Most important is the television. Certainly family members may have differing ideas on what to view. But if the television set is where all can see it together, it can help teach lessons on how to compromise and take turns, as well as what is age-appropriate to view. While kids are awake, TV fare should be family shows. If there are none, talking or reading together is an alternative.
Parents can watch what they choose after the children are tucked in.
Some toys are best kept in a child's room. If younger siblings would spoil an expensive toy, then it shouldn't be in a family area, and keeping it safe in a bedroom is fine. Still, there are merits in learning to play together, talk together, even argue together. When you permit a child's room to become the center of his universe, you are abandoning opportunities for your input, and you are declining to give a child the fullest benefit of your knowledge and experience. Family life is more than what can be learned from a television, a computer, or a telephone.