I turned 13 in 1977, so computers in homes (at least most homes) wasn't an issue.
My son just turned 15, which means he's in the last year of middle school in the system here, and he's had a computer in his room since he was about 10 or so. I can't see any other way for him to do his school work, communicate with his friends, and record (he's a great guitar player).
Most of his school work is based on his having access to a computer for one reason or another; in addition to needing to look things up, his assignments are posted on a site designed for that purpose, and he often hands things in electronically as well.
He goes to a school where most of the kids live within commuting distance, but not close enough to each other to hang out together after school. They skype each other to talk (and also to discuss homework, work on group projects, quiz each other for tests etc).
In his free time, he does things connected with music, and the computer is essential for a lot of it. All his recording equipment is connected to his computer.
Sure, we could have his computer somewhere out in community space in the house, but he'd have a lot of distractions and very little privacy.
As long as he is taking care of the computer and seems to have a balanced life, I can't see any reason to say "no computer in your room".