Let me start by saying that I carry, and like, a 1911 Government. However, that does not mean that I necessarily recommend it to others.
Each individual is different. A "full size" handgun like my 1911 may not suit you. It's a highly effective manstopper, but there are other considerations.
As others have pointed out, a handgun that you carry for self defense is going to have to be something you can shoot effectively. There are a couple of factors in that. One is that most self defense shootings happen at very close range. You don't need to be able to make 500 yard sniper shots for self defense use. Countering that, however, is that self defense encounters where one might use a gun tend to be very intense. The kind of shooting one can do against paper targets at the range is quite a bit different from what you can do when the target is trying to hurt you and you're so scared that your sphincters won't hold and your hands are shaking like a salsa dancer's rear end.
It doesn't matter how great the gun is that you miss with.
Another factor is the size, weight, and comfort of the gun. A gun that's the perfect "manstopper" but is so uncomfortable to carry that you find yourself making excuses for not carrying "this time" is one that does you no good. A gun that you want to carry for self defense is one that you will carry every time. It is for that reason that my 1911 isn't my only carry gun. It is a larger gun and there are some circumstances where it's just impractical to carry. As a result, I have a much smaller gun (Kel Tec P-3AT) that I can carry in circumstances where I have to leave the 1911 at home (or in the car). Choice of holster has a lot to do with that--and expect to acquire a drawer full of holsters in the quest for that perfect fit--but the size and shape of the gun itself does matter.
It doesn't matter how great the gun you don't have with you is.
As far as what the gun shoots is concerned, yes, caliber matters. A .45 ACP is going to be more likely to be effective (given the same shot placement) than a .25 ACP. (.25 ACP--for people who find .22 LR too scary powerful.) There is, however, a lot of range in what is effective self defense and opinions vary on the "minimum" adequate self defense round. Many people, IMO, worry too much about "stopping power" in the sense of ending the fight with one round. My own philosophy is more of the "keep shooting until the threat stops being a threat."
It's great if you can carry, shoot, and hit your target with a .45 ACP, or a .44 Magnum, or a .500 Smith & Wesson, or an .88 Magnum ("it shoots through schools." "This goes through armor, through the victim, the wall, through a tree out side"
). But if those don't work for you as something to carry or shoot, then a .40 S&W, or a 9 mm, or even a .380 ACP will do the job if you do yours. For that matter, if you feel uncomfortable with anything more powerful, a .32 S&W Long can also serve. (Hey, it was good enough for Paul Kersey )
The upshot is that you have to find something that you will be comfortable shooting regularly and carrying every day. Within those strictures, you can then look at size and power. And you may find that the "right" answer for you is more than one gun--a "basic" gun for normal use and one or more "special purpose" guns for situations where the "basic" gun won't fit.
One thing I would suggest is trying as many guns as you can. Go to ranges that have rentals and try different things. Get together with other folk who shoot (if you're in the Indy area, drop me a PM and I'll be happy to go shooting with you and let you try my various handguns: 1911, P-3AT, CZ75B, even a little Jennings .22, Cobra FS, and Nagant revolver). The more hands on experience you have with various handguns, the better off you'll be when you select your own.
Hope this helps.
Each individual is different. A "full size" handgun like my 1911 may not suit you. It's a highly effective manstopper, but there are other considerations.
As others have pointed out, a handgun that you carry for self defense is going to have to be something you can shoot effectively. There are a couple of factors in that. One is that most self defense shootings happen at very close range. You don't need to be able to make 500 yard sniper shots for self defense use. Countering that, however, is that self defense encounters where one might use a gun tend to be very intense. The kind of shooting one can do against paper targets at the range is quite a bit different from what you can do when the target is trying to hurt you and you're so scared that your sphincters won't hold and your hands are shaking like a salsa dancer's rear end.
It doesn't matter how great the gun is that you miss with.
Another factor is the size, weight, and comfort of the gun. A gun that's the perfect "manstopper" but is so uncomfortable to carry that you find yourself making excuses for not carrying "this time" is one that does you no good. A gun that you want to carry for self defense is one that you will carry every time. It is for that reason that my 1911 isn't my only carry gun. It is a larger gun and there are some circumstances where it's just impractical to carry. As a result, I have a much smaller gun (Kel Tec P-3AT) that I can carry in circumstances where I have to leave the 1911 at home (or in the car). Choice of holster has a lot to do with that--and expect to acquire a drawer full of holsters in the quest for that perfect fit--but the size and shape of the gun itself does matter.
It doesn't matter how great the gun you don't have with you is.
As far as what the gun shoots is concerned, yes, caliber matters. A .45 ACP is going to be more likely to be effective (given the same shot placement) than a .25 ACP. (.25 ACP--for people who find .22 LR too scary powerful.) There is, however, a lot of range in what is effective self defense and opinions vary on the "minimum" adequate self defense round. Many people, IMO, worry too much about "stopping power" in the sense of ending the fight with one round. My own philosophy is more of the "keep shooting until the threat stops being a threat."
It's great if you can carry, shoot, and hit your target with a .45 ACP, or a .44 Magnum, or a .500 Smith & Wesson, or an .88 Magnum ("it shoots through schools." "This goes through armor, through the victim, the wall, through a tree out side"
). But if those don't work for you as something to carry or shoot, then a .40 S&W, or a 9 mm, or even a .380 ACP will do the job if you do yours. For that matter, if you feel uncomfortable with anything more powerful, a .32 S&W Long can also serve. (Hey, it was good enough for Paul Kersey )The upshot is that you have to find something that you will be comfortable shooting regularly and carrying every day. Within those strictures, you can then look at size and power. And you may find that the "right" answer for you is more than one gun--a "basic" gun for normal use and one or more "special purpose" guns for situations where the "basic" gun won't fit.
One thing I would suggest is trying as many guns as you can. Go to ranges that have rentals and try different things. Get together with other folk who shoot (if you're in the Indy area, drop me a PM and I'll be happy to go shooting with you and let you try my various handguns: 1911, P-3AT, CZ75B, even a little Jennings .22, Cobra FS, and Nagant revolver). The more hands on experience you have with various handguns, the better off you'll be when you select your own.
Hope this helps.
. All my carry sidearms strictly carry tactical or bonded ammo - not the fancy named crap produced with a gazillion $$$ in advertising backing it up.
. To the OP have fun choosing your CC gun and make sure you post what you got and how well you like it. 
