I'm with the rest on this, there is no such thing as a dangerous dog, only a dangerous owner. I have always had big dogs in my home since I was a LITTLE kid. We've had rotti's, Boxers, dobermans, great Pyrenees, and I currently own a 4 yr old pit who's only issues are severe seperation anxiety and over protectiveness. However he is SUCH an awesome boy.
It's all in how the dog is raised and taught/socialized.