I have personally been a fan of the .45acp for many years but I have recently gone through a down sizing of my gun collection (still in progress) and for personal defense I use the following:

Sig 226 Combat with extended grip and 20 round mag in 9mm. This is a full size pistol and the first full size 9mm I have used for self protection. I at one time carried a Rohrbaugh all the time but I sold it. This is a big pistol and though I am 6'3", I use this pistol in the winter months under a coat.

Smith and Wesson 60-3 Pro in .357. 3 inch pistol with night sights, my 9 months of the year carry pistol. Two speed loaders in a jacket pocket for refills.

Bond Derringer in .357. I use this one quite alot and though its a two shot, it goes into the woods and on many hunting trips with me.