Guess I'm joining the argument a bit late.
No, I don't believe pit bulls as a breed should be banned. My answer to the question of how to deal with pit bulls and other aggressive dogs?
1. Dogs to be leased and muzzled in public whenever they meet specific height and weight standards, regardless of which breed they are. I'm no experts, but something like any dog over, say, 25 lbs. or standing taller than a foot in height.
2. All owners to require a license to own a dog, and they have to take some kind of course in dog training/obedience before getting a license. Every dog owned as a pet to require a specific tag.
3. Dog owners to require liability insurance for every dog owned. The cost of insurance to be based on the breed of dog, and the potential threat the animal poses to other based on selected criteria. You got a little cocker-poodle? Maybe $20 - $50 bucks per annum for insurance. Pit-bull, Doberman, Sheppard, or some other big dangerous animal ... you're talking $7 to $10k per year for insurance, paid before you get a license for the pet.
4. Unlicensed or unmuzzled pets to be confiscated and shot on sight, no questions asked.
These measures would go a long way to solving the dangerous dog problem.