I would recommend that you visit the ballistics tables of any major ammunition manufacturer. The defensive loads I carry are Speer Gold Dot JHP, as that is the ammunition issued by my department, so it's free, well tested, and I have seen its success in the field. There are several other good manufacturers, but here are the numbers on my department's loads:
9MM-124 grain +P=410 foot pounds (at the muzzle)
40 cal. 155 grain=496 FP
45 acp 230 grain=404 FP
180 grain=453 FP
I hope that you are struck by the marginal differences in actual "knockdown power" between the Big Three. I f I, like the U.S. military, were restricted to ball ammunition, I would not feel comfortable with a 9mm. With modern defensive loads, any of the three will serve their intended purpose, as long as the user understands the limitations of the handgun.

are we assuming both are starting from a ready position or holstered? at contact distance, a competent defensive pistol shooter can draw and place a round (or two) in the pump, or cranial vault pretty quick. Said shooter may sustain a defensive injury to the reaction side arm, but you had better make that second count...of course we are assuming competence here.

2 of 2-Absolutely! They took care of me when I didn't have the ability to care for myself, so I owe them the same, should they ever call on me. In addition, I'm fortunate that my father is a more competent outdoorsman than I may ever be, and would be an asset to the survival and welfare of those I am responsible for, because I know that he shares a feeling of responsibility to these same people. But friends and neighbors? When the food runs short, if I have taken them in, and the choice comes down to their kids starving or mine, I want EVERYBODY who would not put the survival of my family before their own, OUTSIDE THE WIRE. For me, that precludes everybody but my parents. I'm sorry if that sounds harsh, but I will accept the guilt for turning them away. It's the price I am willing to pay to ensure the safety and security of my own family.

1 of 2 -I don't know what your family situation is, but I have a wife and two small children (#3 is on teh way). They would be unable to take care of themselves in a real emergency. (I'm not patronizing my wife, she's a tough girl with aniron will, but she hasn't had the outdoor, hunting, or military experience to feel capable of re-supply if something happened to me in an emergency). Therefore their needs are my top priority. I like my neighbors. but with every decision I have to weigh the effect to my family. My own parents?

I have carried both Camelbaks and canteens in the field, and both have their merits. Camelbaks fit nicely into all the new high-speed packs, like the Molle. You don't have to stop to un-holster a Camelbak while hiking. They definitely win the coolness factor. In the Marines I trained with ALICE and Y-Harness, and canteens. When Iraq kicked off, we got all the new MOLLE packs and Camelbaks. Plastic pack frames broke. Camelbaks leaked. I have never been able to break an ALICE pack or frame, nor seen a GI canteen tear or pop. I do prefer the newer LBE over the old Y-harness, as a point of personal preference. For my money, I have an ALICE mountain ruck(the big one) I can make it smaller by pulling the straps, but I can't make a small one bigger if I need to. And have you ever tried cleaning a Camelbak that got funky-tasting? KISS. I vote old school.

A man after my own heart. All the great gear in the world does no good if you lose it to the first thug whose emergency preparation plan was to take what he needs from the sheep.