1 gun would mean that it would be used for cc, target, and home defense. The best gun for this in mho is a 9mm. Probably 4-5" barrel. 9mm ammo is reasonable, plentiful, and powerful enough to be used for cc and home defense. Not sure which I would choose. I have an old Walther P1, but it is far too inaccurate to fill the bill. I keep it in a safe in the bedroom as a home defense weapon. Lots of choices! Glock, Springfield, S&W, ????