Again, "Best Home Defense Weapon if No Gun". If you live in a city, state, Provence, etc. that will not allow you to own a gun, there will probably be restrictions on 'gun-like objects' [airguns, paintball guns, etc.] and some classes of weapons in general such as swords:
1] Know your local laws as to what is permitted, and what the acceptable 'rules of engagement' are.
2] Look for things with little apparent weapons potential - a stout cane or walking stick with a metal ferrule and handle, or, as mentioned, ye olde cast iron frying pan, for example. A replacement hickory rake or hoe handle with a metal ferrule could also be used - [think bayonet thrusts, blocks and counterstrokes] stuff that would normally be found in a house. "He came through the door at me so I just grabbed it...."
3] If Defense Spray - MACE, etc., is a controlled item, think about Dog Repellent, similar to what the Post Office uses. Avoid - at all cost - home made Chemical Weaponry. You will have a hard time explaining how the intruder ended up with a face full of Phosgene in court later.
4] Think about a police baton, nightstick, whatever you call them. Training material is available, and a PR-24 can be a nasty surprise to a miscreant. Personally, I keep a GI tent peg, marked "Souvenir of Annual Training 198X - Dismal Seepage Air Force Station" by my door. Hey, it's a souvenir - I never INTENDED to use it as a weapon...
5] Whatever you decide to use - practice with it. Learn some human physiology - where the weak points on the body are and how best to exploit them.
No-Gun defense has some advantages though - it forces the intruder to physically come to you, strengthening your 'self defense' claim. It also gives you more time to decide your best course of action - "Wow - it really IS your neighbor's drunken brother-in-law who mistook your house for his. I'll shoo him next door rather than poke, stab or brain him...." A gun doesn't give you that option.
People have defended themselves successfully for tens of thousands of years before the advent of firearms. Maybe not as effectively as with guns, but still, they were far from helpless. The most potent weapon is the fighter holding the chosen or available tool.
soupbone