On the whole I am very disappointed with this High Road thread.
I am not going to introduce any new ideas, but I will reiterate them.
Apparently a lot of posters believe that a firearm is the be all end and all tool of self defense, it is not, but then again I am amazed at the number of gun owners who believe that owning a gun makes them an automatic expert on self defense.
You have decided that your are responsible for your self defense. I applaud you for that. Next educate yourself on the topic. The single most important self defense tool you posses is your mind!
For starters read the IMHO seminal work on the self defense mindset
Principals of Personal Defense by Jeff Cooper. This book is not about firearms it is about self defense.
Another excellent starter book is Mr. Ayoob's
In the Gravest Extreme. This book has more of a firearms focus.
Advice.
Situational awareness is essential.
Minimize your exposure to high risk and high crime areas when possible.
Pepper spray is one of the best non-lethal tools available.
I recommend a flashlight for its utility purposes, but I would not trust one as a primary self defense tool. However if you must take a look at Black Bear's products.
http://www.blackbearflashlights.com/
I do not recommend a knife for self defense unless you are willing to commit yourself to years of hard training, and even then accept the fact that there is a very high probability that you will get cut during a self defense situation.
If your circumstances allow an impact tool (with the appropriate training) is an excellent choice. A walking stick is great, an ASP is even better (but not always legal). Keep in mind in many jurisdictions strikes to the head and neck are considered lethal force. I do not feel that Kubotan techniques are ideal for self demesne because it requires closure with your opponent, less than ideal for self defense.
Most importantly again educate yourself. Mr. Ayoob offers excellent classes on self defense and there are a number of great books available. Another fact to keep in mind: you cannot learn from a book what you can in a class. I highly recommend a hands on self defense class.
There is no single tool that is equal to a firearm for self defense, however a firearm is much more dangerous to the user if the user is unwilling to use it (lacks the commitment to use it). There are available alternative, but all self defense tools require a commitment on the users part and some degree of training.
Good luck.