I didnt see where you specified if this was for home defense on away from home defense. I also didnt see where you requested a pistol over a shotgun so I will answer for both...

Shotgun: 12 guage pump action, Mossburg 500 or Remington 870 (I prefer the 870)

Pistol: Glock or S&W M&P... I would NOT go bigger than a .40 cal on either.