Television is pretty ubiquitous these days. The average American spends more than 4 hours per day watching television (source), which adds up to about 9 years of watching TV in a 65-year life. Time is precious, and its easy to get sucked into watching more television than you meant to. Think about how much you could get done if you stopped watching television (hiking, reading, applying for the job you really want).
Additionally, TV has a very significant impact on the lives of children. According to one report, children see about 40,000 advertisements a year (source), and its been shown that because they are less able to understand that commercials are a biased attempt to sell a product, they often believe what commercials portray, sometimes leading to depression. One study says that on average parents have 3.5 minutes of meaningful conversation with their children per week, who in turn, spend 1,680 minutes per week watching TV (source). Who would you listen to? Finally, if your kids are watching hours of TV a day, that means they are inside, more or less stationary. Think about how beneficial to their health and imagination reading a book or playing outside could be!
So try and cut TV from your life. Instead, take a hike with your loved ones, read that book you've always wanted to, or find a project that gets you involved with your community (ex. stepitup2007.org).
For more information, check out newdream.org.