My wife was a lawyer in Malaysia and had to defend some real scumbags. She is under no illusions about how the criminal class views the rest of society. She wishes I could get CCW/ATC to protect her and the kids. She never goes out at night without a can of bearspray. Now we live in North Van and bears out at night are fairly common, so it would be hard for a cop to argue there is no need. Also the cops out here are quite selective about who they hassle for carrying such stuff.
I am not a martial arts type and although I do carry knives, I see the knife as last resort defense when all else has failed. Seen first hand what knives can do and you can win a knife fight and still die. My preference is anything that can increase the distance between you and the threat, which is why I am a fan of sprays. I have used a fire extinguisher as well, which can be quite effective, plus you have a decent club when it runs out.
I also advocate awareness, which seems to be the biggest issue today. I stopped counting the number of times I have seen a girl walking down an alley with her earphone on and engrossed in texting a message. Spotting the threat and taking action early resolves a lot of potential situations, just making eye contact and looking at them, tells them that you are on to them and that the target is not easy prey.
As for people opposed to CCW, few have bothered to crunch the numbers. In the US the FBI estimates that armed citizens thwart approx. 2 million crimes a year and that firearm related indictment rates for CCW permits holders hovers at about 1% and half of those is for dumb stuff like carrying into a federal building. The US estimates that something like 4-5 million new guns were sold in 2009 and over 12 BILLION rds of ammunition sold to civilian and law enforcement in North America in the same year. Meanwhile their homicide rate is plummeting about 4 times faster than ours.