my breed of choice is the American Bulldog. they're just as agile, viscious, protective.... but they're bigger, stronger, more loyal, and they're good with family. you never have to worry about them turning on you and you dont have to worry about them hurting kids and shit.
of course each individual dog will be it's own size and weight. ive seen sum small American Bullies and ive seen sum small Pit Bulls as well. it all depends on the dog itself. but i have 2 American Bulldogs and one is only 7 months and weighs over 80 pounds. he's a monster and he has almost a year and a half to grow. if i had a digital cam i'd take a pic of him to post. our other Bulldog beat the living shit out of a full grown pit when he wuz about 9 months old. now he's around 2 years.... nothing but muscle. pits used to be my favorite breed until i got our AB. i never knew they even existed until we got him. they look similar to pits but like i said they're just bigger and their heads are much bigger. a lot of people mistake my dog for a pit.
another thing i like about the American Bulldog is they fuckin HATE all other dogs (unless it's a puppy and grows up with it). they arent scared of shit, and they'll go out of their way to fuck up another dog.
here's a pic of an American Bulldog i found. dont mind the goofy white guy....