I have lots of guns. My favorite for home protection is an inexpensive Mossberg 20 ga with a pistol grip.
this ? is answered by ONE answer and one only.
a 12 gauge shotgun. PERIOD. end of story. that is the best home defense weapon ever. this isnt arguable.
now, whatever you want to use is subject to debate. personally, i live in an apt complex. i keep my Glock 26 (best 9mm on the market IMO as i have owned every glock 9mm model - the 17 and 19) with me where ever i am and i have access to over 50 rounds at all times in the house. 15 rounds of 147gr HP rounds will stop anything and anyone. I dont care who you are.