RE: my under the bed home defender
Don't forget that the SEALS and SpecOps teams use FMJ ball ammo, which doesn't expand, so the bigger bore makes a much bigger difference. Using modern, high performance hollowpoint ammo there just isn't that much gap in stopping power between the 9mm, 40 S&W and 45ACP. I personally wouldn't feel undergunned with any of the three, and I believe that it's best to pick the caliber that is most practical to the application and not based on (percieved) stopping power alone. Can you handle a .45 well? Then go with it. If you shoot a 9mm the best, or a 9mm is the largest caliber that you can comfortably conceal, then that's the gun for you.
I think that too many people feel apply the same 'bigger is better, ergo smaller is insufficient" mentality that seems to be sweeping the country regard deer cartridges. The fact of the matter is that there aren't very many people that are going to walk away from a 9mm to the upper chest. And if a 9mm to the chest doesn't stop the guy, then a single .45 probably won't either. People talk a lot about "one-shot stopping power," but I believe the 6th rule of a gunfight, "Anything worth shooting is worth shooting twice; ammo is cheap, life is priceless."
Mike