For me it depends on the area and the situation.

Inside my home - pistol, or 12 gauge
Attackers outside - AK47 or mosin nagant for long range
Less than fatal attack unarmed assailant - Cold Steel Koga
last ditch - Kabar TDI knife

It really depends on the situation. The trick is to rise above the force you encounter. The wasp spray really isnt a bad idea. It's good that you have something.

Also might try mixing 5 OZ of Alcohol with Cayenne pepper in an old saline bottle. that will blind anyone. Your first choice should always be to run or get away. if you arent comfortable with firearms dont bother. You can get used to them, but you need to be comfortable with the level of protection you choose.