If your primary purpose is self defense in your home, then a shotgun can't be beat. A longer gun (rifle/shotgun) is also much easier to instinctively aim than a pistol.
I'm interested in hearing your reasons for wanting a pistol over a rifle - then I can give you a better answer.
If you must have a pistol then consider .40/357 as the lower end and .45 as the upper end. Lower than .40 (such as 9mm) just doesn't have good stopping power, and bigger calibers (44mag) will over-penetrate, are hard to control for follow up shots, are uncomfortable to shoot which minimizes the chances you'll actually practice, and are also more expensive which again discourages practice. Did I say practice? That's probably one of the most important aspects of owning a gun, second only to having it safely locked up when you're not around.
As far as picking pistols, I've had a Glock 23 for years and it has served me well. Friends have put 20,000+ rounds through theirs with virtually no problems. They are also easier to train on with no explicit safety to flip.
The old 1911 .45 has made a great comeback. A few years back 99% of the people taking combat pistol courses were using Glocks. And I'm not talking about wanna-be like Dirty Hairy civilians, these were local and federal law enforcement, DOE, etc. Now the courses have a heavy dose of .45s. Like they say, .45 is a fight stopper.
Yes, pistols are cool, but when something goes bump in the night you'll want a 12 gauge.
, i like it because of its size, simplicity, and durability.
