OK, I'm stepping out on a limb and admitting we are the family where the TV is always on in the background. So much so, we don't even notice it anymore. Kids play normally and prefer to be outside or doing crafts, I haven't found any problems with it -- not to say that there are not any problems, just my kids are well rounded, well behaved kids. They aren't at all glued to the TV, if they were I'd probably think twice about it. Actually, they're glued to me! (as they should be I suppose)
They prefer educational shows -- Electric Company and Fetch are DD's favorite. Team Umi Zoomi (usually on demand because I don't like the commercials on that channel) and Imagination Movers are Oliver's favorites. The PBS shows I prefer because the commercials aren't, well commercial. And other then DH putting on sports, he and I never have any adult shows or major networks on ... and I mean NEVER ... there just isn't time for us to watch anything and when we do the kids are in bed. So, by design or not, they are spared from the scary commercials and violence (except for whatever Disney has for their Halloween line up, that is scary enough in my opinion).
Now the computer... we limit that use because they WILL get engrossed and sit in front of that thing for hours on end if left to do so. Computer is not used during the week, ever. And rarely on weekends, it really is a treat. We manage it as you all treat the TV, only certain things, maybe if they are sick and need to relax. If they acted like that with TV, I would limit it too.