I'll disagree on the "drop anything in North America" bit because I sure wouldn't want to count on it if I came up against a bear or even a bigger cat, but I will agree that it is perfectly adequate as a self-defense firearm against humans if you take care to learn how to use it. If you're on-target with a .22 and the guy isn't wearing body-armor, it will get the job done. The key is "on target" and that demands training and practice. Fortunately, as noted, .22s are super-cheap so there's no excuse to not get that level of practice.Despite what anyone says, a 22 has enough power to drop anything in North America.Im not saying that its an ideal self defense weapon, just that its a sensible place to start.With the price of ammo it will actually pay for itself compared to shooting a 9mm or 45 alot.
I love my Walther p22, I allways throw it in my pocket when I hike and stuff.Its small enough to forget your carrying, but large enough to fully fit your hand.
My cousin bought one of the Ruger Lcp 380's.The Walther fits my hand alot better, and definitely has a edge in accuracy.When a target silhouette becomes hard to hit with the Lcp, the little Walther will still hit a tin can at ease.Its a pretty cool little gun for its price.
(One of the things to consider is that some of the firearms mentioned above have .22 conversion kits. Basically you swap out the barrel, the magazine and sometimes the entire slide and you can shoot .22s. Very useful way to get lots of cheap practice while still getting used to the ergonomics of the gun.
I'll disagree on the Glock too. Nothing wrong with the lack of external safety so long as you get trained and use your brain. The only way it can go off is if you put your finger on the trigger and squeeze. The internal safety prevents any other possibilities. If you are in the bad habit of getting your finger where it shouldn't be when it shouldn't be there, then yeah, it can be a problem. They do put a premium on getting trained right, with an instructor who will happily slap your finger and the rest of you if he sees your finger on the trigger before the barrel is pointed at the target. A model 22 (.40cal version of the 17) was my first. I've since traded for a P229, which is a far better made firearm. I found that the Glocks in .40 tended to have minor component failures more frequently than I would have liked. An FBI guy I know confirmed the problem. Said they were a great service weapon because they're light, easy to use and the failures aren't a problem because they have an armorer to examine and rebuild theirs every year anyway...