Why are you letting your kids watch a lot of TV in the first place? We have kids in elementary school, and our rules are simple. No TV or computer time during the school week, and a limited amount on weekend mornings (we don't do church). That's it - no exceptions.
We don't have cable or satellite TV, and because we restrict watching to the mornings, there are no real problems with the shows that are aired. We usually have movie options for them to select instead, as well as PC-based games. Also, for example, when the great Xmas shows are aired in December, I tape them for the kids to watch on the weekend.
Because we set this rule when our kids were still in preschool, they have never experienced anything else, and they don't complain. It is just a rule - just like other families have rules about cleaning rooms, taking out the trash, etc.
This rule has been so great for us. Our kids read books, play games (indoors and outside), practice musical instruments, etc. They don't stay up late watching crap on TV, so they are well-rested for school the next day. And though they may not know what some of the kids are talking about on the playground the next day, it hasn't seemed to interfere with making friends so far. And I'm not sure I really want them being friends with the kids who are addicted to TV anyway - what kind of a friendship is that?