Video games, drinking, drugs, they can all be abused. Shielding your child from them will not make a better person, if they would abuse drugs and they don't have access to them then they will abuse something else.
Though I'm not saying not to structure your children's lives or give them discipline. Limiting their TV watching is OK, and probably good. Having no TV at all is not OK.
And FYI I fall under the "I have one system, and that's plenty." Which happens to be my PC. I've been playing video games since atari and some of the first
real 
computer games (Doom, Wolfenstein 3D) and I've learned a lot from them. There can be quite a bit of skill and strategy involved that you just can't learn in many other places. As well as them being a cheap, non dangerous activity I can turn to just about whenever I need stress relief or have some time to kill.
EDIT: And oh, to drive my point in more, I turned out OK I think. School wise I've gotten straight A's since 7th grade (on my 2nd year of college now). Physical wise I'm fairly active, never been over wieght, played sports, am a martial artist, hike, paintball, ski, etc. And of course the only thing that really matters is that I'm
happy. Again my point is, it's the person that makes the person, not video games, drugs, etc. It's not what you do, but how you do it. OK I think I'm done now...