I shared a room with my sister grwoing up, and we had a telly in there from the age of about six or seven I think. It was a christmas present for the both of us one year - a big present as we didn't get anything else.
It was never hooked up to an arial, and because my Dad worked in electronics they were able to set a master control to put videos on downstairs and feed it up to us. So they had ultimate control. Well, for a year until my parents split, anyway.
After they split we still had it in our room at my mum's, but it was never an issue because my mum made sure we behaved. And TBH, we were more likely to stay up playing with our dolls. Videos were kept downstairs so it was useless most of the time anyway.
As for a computer, we had one in our room from when I was about...thirteen? It was old (had a 4GB hard drive!) but it played The Sims. (which was all I cared about then!) It had been in the living room, but when my mum and step-dad upgraded they gave it to us. It was great for doing homework on, and if my mum thought we were wasting too much time on it, she took away the extension lead it needed.
I also never had internet access in my room, so I don't see why people worry about children looking at porn. You can have a computer without giving them access, and then when they're older and earn your trust, you don't have to worry about the culture shock. I was never allowed a phone in my room like some classmates, but I could always take the home phone in there if I wanted to talk to my friends in private. It's the same thing.