Let's all stop and consider a few other things for a moment. It seems that the biggest argument for high capacity/multiple reloads is a multiple attacker situation. However, what I think that many of the people making this argument are overlooking is the time and distance that will most likely be in play in such a situation.
It is a pretty well established fact that the vast majority of defensive uses of handguns take place at relatively short distances, distances which are usually better measured in feet rather than yards. Even if we assume a "best case scenario" in which only the defender has a firearm, the defender will have, at most, a few seconds before the aggressors are upon him/her if said aggressors are determined enough to brave gunfire to accomplish their goal. If one is perceptive and lucky enough to recognize a threat at greater distance, then said person would be well-advised, and in some jurisdictions legally required, to attempt to remove himself/herself from the situation before gunfire becomes necessary.
Now, to one degree or another, a firearm is a weapon of distance and thus when range decreases to a certain point, the effectiveness of a firearm also begins to rapidly decrease. At contact distance, a convincing argument could be made that a handgun is no better, and possibly worse, than an edged weapon like a knife or ax. This is because, at such close distance, a firearm can be wrestled away from its user and perhaps even rendered inoperable. Therefore it seems to me that one's best hope when using a firearm defensively is to stop the attack before it can reach you.
So, the $64,000 question seems to be how fast can you draw your gun and fire with a sufficient degree of accuracy against multiple determined attackers? Speaking for myself, I'm realistic enough about my skill level to realize that I cannot draw and fire more than a few rounds in the few seconds I'll have if attacked regardless of what type of handgun I'm using and I doubt that very many people could do much better. Therefore, I arrive at my previous assertion that I'm far more likely to run out of time and distance than ammunition.
So, It seems to me that one's two best hopes for surviving an attack from multiple aggressors are as follows: either the gun's mere presence or first few rounds fired causes the aggressors to re-evaluate their life choices and seek their goals elsewhere or the defender's fire can cause the aggressors to pause, duck, or seek cover thus buying the defender enough time and distance to remove himself/herself from the situation. I honestly don't see more than 5-10 shots being necessary to accomplish either of those outcomes and if one of those two can't be accomplished, well most people are probably sorry out of luck anyway. Anyone who thinks that simply blazing away like some sort of action movie hero will save them if confronted by multiple determined attackers isn't being realistic and I hope, for their sake, that such a situation never presents itself.
Now, if it makes you feel better to carry dozens of rounds of ammunition, by all means go ahead. I don't see that doing so would substantially reduce your odds of survival unless you're trying to swim at the same time. However, please don't fool yourself into thinking that all that ammunition is some sort of magic talisman that will automatically save you from the screaming barbarian hordes either; your odds of surviving an attack from multiple people willing to risk being shot are pretty grim regardless of the capacity of your gun. Likewise, please don't be so arrogant as to assume that none of us who have chosen different equipment haven't thought things through thoroughly, I assure you that many of us have. As I said before, capacity is only one piece of the puzzle and it's not necessarily the most important piece.