There was a similar thread a couple of months ago. The consensus seemed to be that the best way to use a .22 for self defence was to get a S&W 617 revolver with a long barrel, hold it by the end of the barrel and whack the bad guy on the head with the butt.
In all seriousness, listen to what everyone is saying. People do get killed with 22's every year, but (a) 22's don't stop/kill quickly so they're not good for defence, and (b) you have to place the shot extremely carefully to have any confidence in the results. A defence pistol is intended to stop a bad guy (ideally without killing them) BEFORE they hurt you or your family.
You need lots of energy, lots of hydrostatic shock, and ideally a great big hole in the front of the barrel to scare people without firing a shot.
If I were using a .22 for self defence and wasn't 100% confident that I could hit an eye socket or similar, I would use the fastest, meanest HP's that the gun would fire reliably -- ie start with CCI Stingers and work back if reliability wasn't there.