Here are the handguns I currently have. My main defensive weapon would be the Walther P 99 in a .40 cal at the top but the smaller Ruger LCP .380 cal is what I carry with me most of the time and I emphasize "most" because if you don't have it all of the time you will probably not have it when you need it.
Please consider the second photo of the North American Arms .22 Magnum. It is ridiculously small but trust me, with a Hornady Critical Defense round at close range, it will get the job done. The trick is to have it with you at all times and this thing will be easy to carry and do the work. I am ordering one this week.