I have a Kimber Custom CDP .45 - it's about $1,300 US and looks like this:
I love that gun. It feels like you're shooting a 9 mm and not a .45. For indoor or close range combat, I would take the Kimber and a handful of clips over any assault rifle. M16/M4 or AKs are meant to be a soldier's rifle, doing battle outdoors, across a longer distance than any self-defense scenario.
After you buy a nice Kimber, take the money you save and buy the wife a tactical shotgun. I also have a Mossberg 12 gauge with an 18.5" barrel. I bought that gun in Florida and tried to make it into the scariest looking thing I could. I really doubted my wife would have ever shot anybody; I wanted the bad guy to run away when he saw the gun. I told her all she had to do was rack a shell, making that special sound, and point it. I bought a full stock with a pistol grip, not the dinky handle thing, a real stock. Then I put a pistol grip slide on the front, and even added a laser sight. It looks like a movie prop. People laugh at the laser sight on a shotgun, but I meant for it to be fired from the hip, and the pattern on .00 buck from across a room is only about the size of a softball. With the big shot needed to kill a person, it's easy to miss with a shotgun.
