I agree with mjkeat on the Hornady TAP. Excellent round. Used extensively by law enforcement.
Plain old M193 ball is also an excellent defense round. The bullet will usually break apart at the cannulure on contact with something soft like tissue, and tumble. This increases wounding potential and decreases penetration.
For those who have fought for it, freedom has a taste the protected will never know!
Or at least they did before political correctness