If you are OK with using a .22 that's fine. My own handgun training discussed "stopping power" and whether or not an attacker might still be able to come after you. The minimum recommended was a .380. Some of the modern .22 loads with hollow points can pack a pretty good punch too so if you are OK using that then that's what you should go with.

It looks like we are beginning to lose track of the intent of my original posting which was to encourage people to not be afraid to stand up and defend themselves. Also if they do decide to get a gun--to learn how to use it--safely. I have taught many people how to shoot and several people on this forum have told me they really liked my post.