Good question that's still relevant in the computer age. I think too many people watch too much TV. For example, I know someone who has at least 1 TV on somewhere in the house 24X7! Personally I probably watch an average of 10 hours of TV a month--at the sports bar, at the car fixit place, at a friend's house... But I rarely turn on the TV myself.
However, I think computer over-usage is also a big problem. I myself am guilty of that--I'm addicted to Hub Pages now. I probably spent 2-3 hours a day on Hub Pages, reading and writing. I've got to find a healthy balance, though Hub Pages is an emotional outlet for me.