Unfortunately there just aren't many easy answers for these types of questions. The law concerning the application of force are highly variable from location to location. Some locations require your response adhere to a force continuum under all circumstances, some locations make provisions for using a level of force higher than that of your attacker under specific circumstances. Even if you respond with a level of force lower than that of your attacker you could still be in trouble in many places. A short visit with legal council in your area is the best way to sort out the legal angle.

Something else to consider; weapons that used to be referred to as "non lethal" are now referred to as "less lethal". An item that is less lethal to an adult male is going to have a much more dramatic effect on children or older adults. This means that options are going to be highly variable based upon your own living arrangements and concerns.

You're own personally level of fitness and the amount of time that you are willing and able to devote to training with any defensive tool or technique are going to have a tremendous influence on your list of options.

I sincerely hope this post doesn't sound like a dodge.