In the movie the kid travelled back in time to fix what went wrong in the past and therefore change the present.
What these movie makers fail to realise is that if you have changed the past then in effect it was done right in the first place, thereby making it ok in the future/present and therefore making the trip in to the past unneccessary.. which means that you wouldn't go back and change things.. but then that means that you didn't go back to fix things so then it would go wrong so you would have to go back etc etc etc etc....
My solution: DON'T MESS WITH TIME! Take Marty McFly's advice and leave things well alone!
Instead of time travel I think a time window would be more practical. This would mean that you could see what effect the decision you make today effects your future, without messing about with something that shouldn't be messed with..
... and also remember where you put your keys last night!