I don't like to get into gun debates, but so far the discussion seems like people are arguing about stuff they only have an opinion on, rather then any experience. I don't have much experience, but I'll offer what I've seen.
Several years ago I got my concealed carry permit and any place I'm legal to do so, I'm armed. I have perused concealed carry forums and sites and come across a lot of great information and discussions.
First off, reaction time is a big factor in any situation. Most people who are holding a gun, or other weapon on someone, typically isn't expecting them to counter attack. If someone who is carrying a concealed weapon pulls the weapon to defend themselves, the aggressor has a moment of hesitation, which can be more then enough time. Recall, unless the aggressor (criminal) is trained, his/her mind has to realize you're drawing your weapon and then react to it.
Second, some of the concealed carry forums create scenarios asking what the readers wish to do in certain situations. Interesting enough a very high percentage reply with some form that doesn't require drawing their weapon. Realize that most criminals are not going to fire, but if you provoke them, then they typically react by firing their weapon. Hence the reason why concealed carriers on the sites I follow don't want to draw their weapon until they feel there's no other option. Note, the overall feeling by the concealed carriers on these sites was they got their permit to protect themselves and their families, not to be heroes.
Third, those who carry tend to decide prior to an incident how they are going to react. For instance, determine beforehand how you would react in situations with your family with you and the aggressor(s) are only threatening. How would you react in a place of business when there were more then one aggressors, or one aggressor with a firearm, or some other weapon. At what point do you draw your weapon and what do you do when your weapon is out and in hand?
In regards to the last I've decided that I will never pull my weapon unless my intent is to fire it. I will never put my hand on it unless I believe a situation is about to turn for the worse and I may need to draw it. I will also never show that I'm armed, since this typically only escalates the situation.
I'm tired and I should be in bed, so I'm betting I'm going to wish I hadn't posted in the morning.