The Springfield XD's and XDM's seem to have a reputation for reliability. I've never fired one, but going by what I've read, they're worthy of looking in to. I figure any one of the "big three" semi-auto calibers (.40 S&W, .45 acp, 9mm) will do the job when properly equipped with a premium hollow point ammo (gold dots, Ranger Sxt, etc.). I really don't know what I would carry if I felt a real need -- probably go with the old and reliable .45