My son is 8 and I have, within the past few months, been letting up on all the electronic restrictions. He really likes Minecraft. Some days he'll get to play for a couple of hours or more, some days none at all, some days just for a hour. It just depends. I play too, so we Skype together while we play. We probably only do that once a week or so though.
He still plays outside, he still plays with his toys, he reads books on his own time, he gets his school work and chores done, so I don't have a problem with it. I spend a decent amount of time on the computer myself.