Great info Spicey and PB.
One thing i'd like to add is something about the SBT.
PB,you see the SBT you have posted its a great specimen and show quality no doubt.
The thing is living in London,England i can count the number of times ive seen an SBT that looks like that on both my hands.
I see those SBT on tv or at dog events/shows (that particular SBT conforms to the standard written by the KC way back,dont ask me why but when you do spot one like that we call them *king staffs* )
Now obviously after the KC made the SBT an offical breed in 1934/5?? the show breeders bred for that short legged,large headed pooch.
Thing is ive learnt alot about the origins of SBT (way after i should have) from reading various threads here that led me to research for my inquiring mind.
Thing is the original SBT (obviously bred from bull and terriers) were quite a bit leggier and more *terrier* faced than that of the show SBT.
I believe many of Englands SBT are the legacy of the breeders who didnt go the show direction but rather bred the more game dog keeping its pit fighting dog looks more so than the dogs you see at crufts etc.
BYB no doubt but all papered up (KC registered) and carrying bloodlines from the 1st SBT (maybe before the breed was reconised officially)
I would bet the US has more correctly cormformed SBT than England does.
Heres quite a few examples (picture wise) of what im talking about.....
CH Gentleman Jim,a photo from 1936,see how he differs from the above pooch,leggier,thinner muzzle and to me better looking...
This is Lazy,my bitches father,he is more similar to the SBT PB posted (structure wise)
This dog also has that look too...
Below i'll post the SBT that you'll be more likely to see if you come to England,leggier less stubby dogs weighing more than 38lbs (i'd say 50lbs minimum)