In this order:
1) Firearms: Even in "gun-control" countries and regions, and even in dense urban areas, it is often still possible to jump through the hoops in order to keep actual firearms AND ammunition in your home. It might be expensive, it might take a long time, and it might be a pain in the ass, but it might also save your life.
2) "Alternative" Guns: Airsoft guns, BB guns, flare guns, nail guns, and spear guns are all things that most people DO NOT want to be shot with. Disclaimer: Your result may vary.
3) Crossbow & Bolts, Bow & Arrows: These are still commonly used for hunting large game animals, and anything that can take down a bull moose could also take down a two-legged predator.
4) Tasers: Law enforcement use these puppies often, and they are not called NON-LETHAL...they are called "Less Lethal". You could still fuck someone up with a Taser.
5) Speaking of puppies, having a couple of big-ass guard dogs around the house is always great in my book. I love dogs, and I love how they bark and growl like pissed-off rabid animals when annoying strangers knock on my door.
6) OC Pepper Spray: This shit sucks the big one. Again, "Less Lethal".
7) Collapsible Baton: Good for concealed carry if necessary, but not good if the other guy has a projectile weapon (any of the previous mentions, including the dogs).
8) Combat Knife: Not your folding pocket knife, I'm talking about something an old-timey pirate would carry. For the record, if you're ever involved in a knife fight, then you've already lost. Now it's all about who goes to the hospital with the least amount of blood loss.
9) "Tactical" Pen: Slip it in your pocket and hope you never have to resort to jabbing someone in the eye with it.
10) Brass Knuckles: Better than nothing, and you'll misplace someone else's teeth if you use them correctly.
11) Mad-Crazy MMA Skills: I'm being serious. Hit the heavy bag every single day and learn how to keep yourself conscious while sparring and wrestling against people who are bigger than you.