Being a Rottweiler owner, I run into this stuff all the time. I cant take my dog to town and take him for a walk on the safety of a sidewalk. I am stuck walking him along the side of the road in the country where morons have never heard of slowing down for people walking. When we go camping there are always uneducated people that freak out when they see me walking Gus. "Run for your lives!!! Hide the women and children!!!" I actually have an edge when we go camping. The host loves my dog and usually stops to play with him for a few minutes on his rounds.
I say get the dog you want and plan ahead. Most of the time you are going to only find trouble when you have a Pit, or Rottweiler. In all my years the nastiest dogs I have ever ran across were Chows, and Dalmatians of all things. I would be willing to bet that every one of those had no proper raising, or spent their life on the end of a chain with no attention at all.