I feel sorry for everyone who feels the need to carry weapons around. Either having such a dangerous life would suck, being paranoid would suck, or being a (concealed) psychopath would suck. If you think its cool or whatever, you are a psychopath in my humble opinion. I have never carried around a weapon. I may have consciously put a cigarette lighter in my fist once in a while, but I carry those around anyway and not for that reason.
Violence solves nothing. Except in games.
On a side note, I do own four replica swords which I keep in my room. One is a katana which might bash someone's head in if necessary. I would only use it to threaten a possible intruder though. I'd dread the consequences if I'd actually seriously injured somebody.