When I only had one or two kids, I seriously restricted their Screen-time. TV, Computer, even their own kid-size computers. One to two hours was the absolute max, no more than 5 days a week and they rarely, if ever, watched commercials. I was a Kindermusik teacher! Life was about activity, movement and learning!
Now, I have three kids and my schedule is overflowing. Only one child is in school full-time and I'm trying to earn an income by writing and editing from home when I'm not at my wine store. Sadly, screen time has increased. It's still limited to right around 2-hours, but sometimes it goes over, and it's more often 6 to 7 days a week. They still don't see commercials (thank you, Netflix) and they have to have mommy approval (no Sponge Bob, thank-you-very-much).
They become mermaids or wizards, horses or dogs, secret spies or even mommies! They make up new stories, new songs and even write books! The TV, then, is not a brain-drain, it is inspiration for hours and hours of play!
Everything has a flip-side. Use TV wisely and it can truly have a positive impact on your life and your children's. No, you certainly don't need television to spur imagination, but when you need 23-minutes of time for you (the exact length of any Nick Jr show without commercials), it doesn't hurt!