I'm sorry, but I really have to consider the whole "X million X were rounded up and exterminated BECAUSE THEY DIDNT HAVE PISTOLS" stuff bupkis.
There is NOTHING stopping any army from invading your house. Your stupid hand guns are shit compared to what they can do to you. Your choice in weaponry is already restricted by to the point where you can't do a damn thing against any government agency (like those listed as killing "X many X"'s).
The only guns I personally see any reason for civilians to own are hunting rifles. Pistols are pointless, automatic weaponry is pointless.