RE: 40 S&W or 45 ACP?
1911 style .45 for me John Browning hit the nail right on the head with that design of course some modern upgrades never hurt just to improve on Mr. Brownings idea,I regularly ring my 100 yard gong with my Springfield just for fun.At combat ranges(30yds.and under)I have no problem keeping them in the kill zone even with multiple rounds i.e. double taps,etc.It even shoots good on the move but as with anything the best weapon for home defense is the one you have.Also LOTS of practice never hurts not just shooting also stoppage(stove pipe,double feed,etc.)clearing,reloading drills,dry firing(with snap caps)sight aquisition,etc. only improve your skills to the point where they become second nature.