On a serious note (since he did ask for advice, after all): A revolver is an excellent choice for a first handgun and an all-around logical pick for a self-defense firearm.
You definitely do not want a .22 or similar small calibers like the .25 ACP seen in a lot of the cheapo guns like Jennings autos, etc.
Most professionals will recommend .32 (rarely) or .38 caliber at a minimum to provide lethal one-shot stopping power. There isn't much demand for .32, you're more likely to find handgun choices in .38 Special, .357 Magnum, quickly jumping up to .40 & .44 Mag. 9MM and 45ACP are both popular for automatics but due to the cartridge design they require special adapters (moon clips) for user in a revolver and you won't find many designed for them.
For an apartment, I'd stick to a .38 Special with hollowpoints. A .357 Mag or bigger is just too much for a confined area. A shotgun is also a good choice. Loaded with buckshot, though, it's still capable of hitting someone in the next apartment. Think about using something smaller. Pump actions are nice and simple, but -please- don't fall for the Dirty Harry "Pump the gun so he can hear it" macho crap. If you have an intruder in your home the last thing you want to do is to enter the room with an unloaded weapon. What are you going to do if it jams?
Finally, unless the intruder is already in the house and threatening a member of your family, the best thing you can do is to lock yourselves in a room and phone the police. If an intruder is really ambitious and breaks in to the home, then breaks in to your locked room after you tell him that you've called the police, then you let him have it. Remember, you're likely still going to be wiping the 'sleepies' out of your eyes while the intruder(s) is/are wide awake, fully alert, and juiced up on adrenaline (at a minimum). You don't need to attempt sweeping the house when you're not even sure what you're dealing with. Let the pros handle that.