As soon as you said self defense the .45 ACP in almost any decent handgun is the right choice. It is one of the few, if not the only round specifically designed to stop a man dead in his tracks, period. You can view ballistic charts, listen to industry hype, but the full weight 230 grain .45 delivers just the right speed, bullet diameter and density in perfect combination to stop any man. The recoil is different to the .40 or the 9mm but I would not say more. The 9mm and .40 are high pressure, high velocity rounds and usually produce a very "snappy" or "jerky" recoil usually canted to the side in most handguns. The .45 is a much lower pressure round that produces more of a straight back and slightly up recoil in most handguns.