Reader Grady P has noted two recent stories from Houston which are both disturbing and comforting at the same time.  If these sorts of stories don’t deter at least some crime, and point toward the maxim that “an armed society is a polite society” then nothing will:

First: “Police: Homeowner kills suspect during tool theft“

Second: “Suspect killed in alleged carjacking attempt“

Well, the ultimate is probably this one…it’s rather graphic so if you don’t like the sight of blood, don’t look:
http://www.xdtalk.com/forums/xdtalk-chatter-box/91751-warning-graphic-armed-robbers-try-rob-off-duty-cop.html