the am staff (akc)and apbt(ukc, adba) are different breeds but fall under the "pitbull" catagory.
here is the history of apbt
THE REAL PIT BULL--Your online source for American Pit Bull Terrier info!
amstaff
American Staffordshire Terrier (Amstaff)
as a proud owner of an APBT they are wonderful loving dogs that have a high intelligence level and are willing to please which makes them highly trainable. They are also very athletic and that makes them ready for a variety of canine sports. My boy loves people and is everyones best friend. My pitbull like a lot of them is a big baby. He loves to cuddle and play with his toys and sit on mommys lap (yep all 50 lbs of him). He even loves wearing his jacket or sweater, if i take it off him he will try his best to get it back and actually tries to put it on himself
I am glad you asked about the breeds instead of just relying on the media to form an opinion of the breed. A lot of the news stories that involve "pitbulls" are not usually "pitbulls" but other breeds that resemble pitbulls.
http://www.understand-a-bull.com/Findthebull/findpitbull_v4.swf
did you find it?
alot of the mistaken pitbulls are breeds that are capable of human aggression or apbt that is mixed with something. (i am not saying its impossible for an apbt to be aggressive in the worng hands).
The truth is if I was to have children I would have no other breed around my family or children. They are great family dogs because they love people and especially their family.
We have 3 right now at my house (only 1 is mine) and they are wonderful no problems they can all play together and never one incident. The 3 at my house get along like best friends even snuggle together.
They don't fight just because, there is no bloodlust in them, they dont attack for no random reason. That is something that has to be forced on them by people that want to match dogs.
OP, if you really have intrest in the breed next time you see someone walking with one talk to the owner about their dog and pet the dog. I bet you will find out that they are "just dogs" and most owners are just regular people (some of the owners are a little odd though, but in a good way

) but we love to talk about our dogs.
ps. i play tug of war with my boy and sometimes i win sometimes he wins...it doesnt make them mean or aggressive. Seriously, in that respect they are not like any other dog breed. Its a game to them, a way to burn off energy its not going to train them to be vicous. We play tug of war until he gets bored sometimes and goes off and finds his tennis ball and then its time to play fetch. I leave his tug toys in sight and when he wants to play that game he brings it to me, the same as he does with his jolly balls or his tennis balls or his chew bone. A toy or a game is not going to train a dog to fight or attack.
http://www.badrap.org/rescue/myths.cfm scroll down to the myth titled "doesnt forcing a pitbull to hang from a tree branch make him aggressive" it talks about the tug of war myth