Well this isnt exactly a serious thread but it does offer an opportunity for throwing out hypotheticals. Okay, suppose a hitman is coming for you. Or even several of them. It's quite doubtful they're real professionals. Suppose you choose not to leave. You have money, stock up on supplies and barricade yourself in, if you choose to fight them. Why? A sniper cant hit you if your not out in the open, supposing they would even be a sniper, which I doubt. When you barricade yourself in the building you force the enemy to come to you and you ruin his opportunity to surprise you. By barricading yourself inside a building, you set up several opportunities to ambush your attacker.
No, I would not risk my life to do this, unless I absolutely had to. This is all theory. If you could move, you should move. Theory, however, is quite fun, even if it all collapses in the heat of the moment. So, here goes:
I most prefer the methods mentioned here, though quite a few can be tossed out in this specific setting... as this isnt platoon based urban combat in wartime.
http://www.hardscrabblefarm.com/ww2/fm3150.htm
Scroll down to the defense and skip anything that has to do with squads. Yes, it is a WW2 assault/defense handbook.
Hopefully your assailant wont catch you sleeping, even so, the breaking and entering should wake you up. I know most of those who picked out a huge arsenal were most likely joking, but to any who werent, be realistic. Pick one primary semi-automatic weapon (or shotgun) that you are comfortable and experienced with, and one semi-automatic handgun that you are also comfortable and experienced with. Semi-automatic handguns are generally preferable to revolvers in this situation but its ultimately personal preference. Any talk of automatics or large arsenals is unrealistic... you can only (effectively) use one weapon at a time, and with an automatic you are more likely to expend your entire clip on nothing other than air in your excitement. This is why the US Army changed the M16 to a 3-round burst, and itchy trigger finger will eat through your ammunition very quickly and you wont accomplish anything at all. A semiautomatic is still rather fast (police officers often fire a lot more rounds than they should sheerly out of the excitement. Many will swear they only fired a single shot when the clip shows that they fired 4 or 5.), but, it isnt nearly so bad as an automatic, and will do the job just as well if you find yourself unexpectedly face to face with your opponent. Keep a good stock of ammo but not so much to weigh you down. Acquire whatever body armor you can if you have time, but comfort and ease of movement is always important and you can forego anything that isnt truly useful. Anything other than a bulletproof vest isnt going to help you an awful lot. Body armor is generally illegal though, so you probably wont find anything.
There are a lot of questions that have no right answer. Lights on or off? I would pick off. But suppose you can't see well at night (my fathers pupils dont dilate very well) - leave the lights on. There are a few neat tricks you can pull with lighting. A few ideas follow:
1. Leave the downstairs lights on, but turn all the lights off upstairs, and pick the room that the least light spills into from downstairs to defend. This way, your eyes will be adjusted to the darkness, but it will take time for your attacker's eyes to adjust. The disadvantage here is if your upstairs, escape is no longer an option, if it were an option in the first place.
2. Set up a flashlight in a room with only a single entrance (securely block up any windows), pointing towards the doorway, aiming for eye level. Position yourself elsewhere in the room, in the place least illuminated by the flashlight. Close the door, place a towel under the door so the light does not spill into the hall, if you have time (check this for leaks in other places beforehand.) so that the enemy isnt expecting to be blinded. The attacker will most likely assume that you are holding that flashlight, at least at first. The flashlight will also blind the attacker. Then the attacker has two options: walk into the light and fully expose himself to a hidden enemy, or, if hes intelligent, disable the flashlight. If you feel that having a flashlight on in the room will impair your night vision, keep one eye closed while you wait for the attacker. That way if the attacker disables the flashlight, you at least have some degree of night vision, while they have none. The best position for the flashlight is somewhere where the enemy must enter the room to deal with the flashlight (neither you or the flashlight should be in a position where the enemy can see you from the doorway). This way, he is more likely to mistake the flashlight for you, and enable you to deal with him before he can think to take your flashlight out of the equation.
The best flashlight to use for this is one which creates as little splash in the room as possible, but is still blinding (narrow beam). You want as few reflective surfaces in the room as possible, they bounce light. This includes white walls, if you had time and intended to seriously use this tactic (you always want more than one tactic, but obviously something comes first or becomes the most favorable option in the situation), you would want to make all the walls as dark as possible, (painting black?). You want to place the flashlight a good distance forward away from you, and yourself in the rear of the room.
Its all just theory anyway. Have fun thinking about it.
Oh, and PS... when defending dark places, never carry a flashlight. You might as well walk up to your opponent and ask him to shoot you. They can be useful on the offense when clearing rooms, to some degree, though that screams for you to be shot as well. Never carry a flashlight when defending, ever, ever, ever.