This is more water cooler-quality talk, but DD8 reported this weekend how she's noticed that playing Minecraft on the computer has had a big impact on the development of her typing skills, because she enters various line commands (cheat codes) each session. I had taken notice as well.
It's also helped her develop familiarity with command-line interfaces, but she's not in a position to appreciate that.
I can definitely attest to the sleeplessness issue (since it happens to me on occasion), so the ideal would be to unplug from the computer/console/i-device at least an hour before bedtime. I don't really see the same issues around television, since it's a passive form of entertainment.
