I don't get the demonizing of Xbox. I think of Xbox as a nice stress reliever for my son, and a team building event for he and his friends. They wold take it on the road and play in the cars and late night in the hotels. They had a blast, and it was great for them. They love to make their own player, and dynasty teams. Since my son strives to be a good baseball player, person, and student, I don't put any restrictions on him. I never have. He has been lucky to have good coaches, and good teammates that work hard. I would agree that having the right friends/mentors goes a long way.
Also, I have seen a couple of posts about not pushing them too hard. I don't know that I agree with that policy. At some point, they need to get it. If they aren't getting to that point, what do you have to lose? They might quit? They weren't performing or working hard enough, maybe some real talk will help them see the light. There were many times I told my son the cold hard facts, and I do admit that I crossed the line sometimes, but my son eventually took the ball and ran with it. As a High School Player, I don't have to be the bad gyum and he long tosses, does the extra high school workouts, and goes to the gym daily. His coach paid him a great complement. "He said he wants to be great, and you can't teach that."
I beleieve if your sons are having motivation issues in 8 th grade when they should be having fun, there is a big, red flag.
Xbox can be a stress reliever and I am fine with that. It is also a social event. With xbox live a group can get together and play online. Not really that much different than the 3 way telephone conversations we had when I was a kid. However, it can be very addictive. Sometimes a kid with forego his responsibilities to play. Even my kid will half ass his homework to finish quickly and get on. Moderation is key.