For the 22r of handguns, you want a Glock hands down. 18yrs ago I was in your same situation of not being too familiar w/handguns other than my .45 cal cap/ball revolver. I went in to the gun shop thinking I wanted a 9mm Baretta, but after discussing my wants/concerns, the shop owner recommended the Glock 17. The 17 was too small for my hands, only my middle finger and ring finger were on were off the grip. The Glock19 was on 3 month back order, so I went with the Glock 22. A .40 cal is more expensive to shoot, but it does have more stopping power than a 9mm, and less of a recoil than a .45. If cost of firing is an issue, I would go w/the Glock 19. As mentioned Glocks don't have a separate safety, it is built into the trigger, and releases as you pull the trigger. While this doesn't sound safe, 1000's of tests have shown otherwise, and as far as I know, no one has ever been injured or have had the gun go off accidentally from the built-in trigger safety. There are stories of accidental firing of Glocks out there, however non are due to the gun itself, but from human error, i.e. not checking the chamber(something that one should always do regardless of type), un-holstering w/finger on the trigger(a no no for any handgun), or handling with finger on the trigger when not ready to shoot(something you aren't supposed to do w/any firearm).

For home defense I would go with a 12 gauge shot gun, pump or semi-auto. With a shot gun you have the visual deterrence w/the large barrel and audible with a pump, you don't have to be as accurate(helpful under duress or fog of just being woken-up) and you are less likely to hit/kill someone(through the wall) in another room if you miss.

Under CA law you have to have your handguns in a locked container when in a vehicle or motorcycle, a container other than your glove box or trunk, so no, you can't have one in your car for self-defense, unless it is on your person and you have a concealed permit.