The gun I have with me the most is the Ruger LCP in .380, because it's so small. If I feel I might need something more potent, I might also carry either my my Ruger SR9c or my Taurus PT145, but I'll usually still have the LCP with me. Sometimes it's not practical to have more than the LCP with me, so that's what I live with.
I have a .32 S&W long revolver made by H&R, and while it wouldn't be my first choice to protect a member of my family, I had toyed with the idea of letting my sister use it for defense. Mostly because she's handicapped and has limited arm strength to handle recoil. A better option for her in that respect might be the Hi Point .380. Some people might laugh at the Hi Point, but it's hands down, the lightest recoiling centerfire handgun I own. Maybe the lightest that there is. And mine's very reliable.