In th 21st C. it makes the most sense to use a handgun, revolver or semi-auto, in a caliber starting in the .4" range. If you're not willing/able to hit the range to practice with said firearm, then I recommend a pump shotgun.
even that's not a sure thing, and a khuk or other knife is a capable tool thatn can be pressed into service as a 'backup' weapon, but they're messy and require much training.
And if you are a collector of weapons, or are trained, and have to go to court because you killed someone with what the 'jury' might consider a brutal weapon used in a brutal fashion, it could cause problems in some locales...whereas a modern firearm used in defense woun't warrrant any undue attention from the law...it is the modern tool for the job.
My 2c