Pistols: While I personally think pistols are inferior to shotguns for home defense, they are nevertheless a hell of a lot of fun to shoot and if you're looking to concealed carry a firearm than you'll need a pistol. Note: if you're interested in concealed carry, check your local laws involving becoming certified to concealed carry as well as where you can and cannot carry a firearm.
The biggest decision you'll have to make when purchasing a pistol is the caliber you will wish to purchase. Common pistol calibers include .22, 9mm, .357 SIG, .40, .45 ACP, and more. What I'm about to say is a strictly personal opinion: go with the 9mm. Nine is fine. The advantages of a 9mm pistol are that they typically come with a higher capacity and are much cheaper to shoot. More important than what gun you buy is how experienced you are firing that gun. Some dumbass who buys a Desert Eagle .50 to look cool is far less effective than a well-trained individual with a 9mm. Cheap ammunition gives you the opportunity to regularly take your gun out to the range to plink away at targets. However, let me repeat my advice: look around and find out what gun works best for you. Go to a gun show and handle the different types, ask a friend to take you out shooting. If you end up buying a .45, more power to you.
Over the weekend, I just purchased a Springfield Armory XD-M 9mm handgun. You can read about it here:
http://www.springfield-armory.com/xd.php. It's one of the most sought after guns on the market currently. The 9mm model is basically nine with the body of a much larger gun, allowing the magazine to stack nineteen rounds. This capacity is just ridiculous for a 9mm. I'm really happy with this gun, though it may be a bit out of your price range. I payed $600 for it at a gun show.
I don't mean to give you the impression that a 9mm is ineffective, far from it. Which brings me to another thing you need to be aware of, regardless of what caliber you purchase. When you are purchasing rounds for target practice, you'll probably want to go with
full metal jacket rounds (FMJ). They're cheaper and since you're not looking to shoot to kill, they're the best option. The world wouldn't come crashing down if you used them for home defense, it's just that they aren't the right tool for the job. Ignore
frangible rounds. They are apparently good for indoor shooting, and that's about it.
For home defense, you will want to purchase
jacketed hollow points (JHP). You've probably heard of hollow points and have some idea of what they do. Basically, a hollow point round expands and deforms when it strikes a target. The exit wound from a hollow point round is substantially larger than the entry wound. The 9mm has substantially better put down power when you are firing hollow point rounds. They are your best bet for home defense. Hollow points get a bad rap, because truthfully they aren't a pretty thing, but there's nothing pretty about killing a person. Which leads me to a quick discussion about the do's and don't's of home defense.
Home defense: Ignore what you've just read in this thread about home defense. The event that you will ever have to defend your home using a firearm is statistically improbable. In the unlikely event that someone breaks into your home while you are in it, the absolute last thing you want to do is shoot them. There are moral, legal, and psychological dimensions to this, but just keep in mind: killing a person is awful. I'm glad I'm not saying this from personal experience. It will undoubtedly bring you a great deal of legal trouble and will cause you and your family a lot of psychological pain and stress. If some asshole wants your television, let him take it. Your possessions aren't worth taking a life over, not ethically and not legally. Families will very often sell their home after a home invasion that ended in a shooting, such is the psychological stress of killing a person.
The only time you should use your firearm against an intruder is when you believe your life or that of someone in your home is in imminent danger. I understand that a home invasion is a very scary experience, and maybe just their presence alone is enough to make you feel that your life is threatened. Here's what you should not do, however:
-Pump your shotgun loudly and menacingly to scare someone out of your house. I know it looks good in the movies, but I say again: the only situation where a gun is required is one where your life is being threatened. Loudly cycling your gun for effect has no place in such a situation. People also have this odd notion of loading up with blanks to "scare" an intruder away. Your typical handgun is unable to cycle out a blank round automatically without being adapted. You would need to eject the casing and cycle the gun by hand. Go ahead, I'm sure the intruder doesn't mind waiting. Aside from that, as I'll say a million times, home invasions aren't the time to start getting clever. If you need to shoot, shoot to kill. If you don't need to shoot, don't shoot.
-Shoot to wound. You are not capable of shooting to wound. Trained law enforcement officers cannot consistently and accurately shoot out someone's knees or whatever other fantasy you might dream up. Police officers are trained to shoot for the “center mass”, which is the torso (chest, stomach). This is the largest part of the human body, and it also has the advantage of containing nearly all of your vital organs. Shooting to wound will get you killed, don't even try it.
Also, United States courts historically look down on shooting to wound for the simple reason that it tends to prove that you weren't in a life-threatening situation after all. For the umpteenth time, only in a situation that directly threatens your life or that of someone under your protection should you even consider killing someone. Your ethical views may differ, but American law takes an extremely dim of shooting people. Probably too extreme, but those are the laws and you have to obey them.
What you should do: Ideally, in a home invasion your best bet would be to gather your family members in one room and lock the door. Dial 911 while covering the door with your firearm. You can loudly tell the intruder that you are calling the police and that you are armed. Wait in the room until the police arrive and follow all instructions. If the intruder is psychotic enough as to actually attempt entry into the room, this is a clearly intended threat to your life, and you are fully justified in defending yourself.
Obviously, this scenario is only an ideal and in the unlikely event your home is invaded you may not have the opportunity to gather your family together. Just do not, for the love of god do not go around like some cowboy pumping your gun and trying to shoot theirs out of their hand. For the last time, this is serious business.
OP, if you have any additional questions that can be answered, I'd be happy to help. Also, talk to the guy down at your local gun shop. They're almost always pretty knowledgeable and more than happy to help. Make sure you follow all your local, state, and federal laws regarding gun possession and make sure to train often.