While I agree that breed-specific bans are problematic, I'm not convinced by those who claim that Pit Bulls aren't aggressive or dangerous.
A study published in the Journal of the American Veterinary Medicine Association in September, 2000 reports that in the 20 years studied (1979 to 1998) "Pit-bull type dogs" and Rottweilers were involved in one half of approximately 300 dog bite related fatalities in the US [http://www.dogbitelaw.com/breeds-causing-DBRFs.pdf]
. Another study of American and Canadian dog bite related fatalities from September 1982 to November 2006 produced similar results, reporting that Pit bulls, Rottweilers, Presa Canarios and their mixes were responsible for 65% fatal dog attacks [http://www.dogbitelaw.com/Dog%20Atta...20Clifton.pdf]
. This study also noted: "Of the breeds most often involved in incidents of sufficient severity to be listed, pit bull terriers are noteworthy for attacking adults almost as frequently as children
." and "They are also notorious for attacking seemingly without warning
, a tendency exacerbated by the custom of docking pit bulls' tails so that warning signals are not easily recognized."