RE: homeprotection
12 guage coach gun- light, cheap, and short enough to use in close quarters. If you are prepared for a fight for your life, a long gun is the only way to go, whether it be a shotgun or a carbine chambered in a rifle cartridge. As far as the concern about overpenetration goes, a .223 hollow point will punch through a lot less building materials than a typical 9mm/40S&W/.45 ACP round and its a lot more lethal.
Forget about the nonsense about'racking' a shotgun to scare an intruder- it onlythrows awayyour homefield and any other tactical advantage you might be lucky to haveby telling the BG "hey I'm over here!"