To expand on this a bit further, any working class dog, really needs that kind of attention:
Whether it be a "Pit bull, or a Shepard, or a Doberman, or a Border collie, a whippet ect... Working class dogs need to be worked, or they do get spiny in the head, and become destructive, they will be active with or without you.
I have a dog (there are pics and a vid of her, in the dog thread) that we thought might be a pit cross when we got her from the pound, as she has grown up, I think she is more likely a whippet/dalmatian cross. As many people from this board that have met her can attest she is full of energy all the time. Not only that she is incredibly thick headed. She is a handful and a life style, it forces my fat ass to get up and take her for walks, or throw a ball, or just wrestle with her in the living room. This is my wifes first dog, and has been a great learning experience for her, but I would have never picked a dog like this, if it was only going to be her looking after "ate" (yes my dogs name is ate, it is pronounced ah-tey and in Greek mythology she was the Greek god of mischief. I was fortunate enough to have an ex that bread shepherds that are on current active duty with the RCMP, as well as the coast guard, and other search and rescue organizations. My ex was a great teacher of what a dog needs, not only to be healthy but happy.
If you are thinking about getting a dog, get one that fits your lifestyle, not just because you think it looks cool.