It would depend greatly on the situation at hand. I would try to have the safe secured with a single quick-opening lock, key around my neck if possible, located in a secondary room where I slept, preferably behind an obstacle (closet door, bed, dresser, etc.) to provide some cover if the intruder did burst in while I was still arming. I will assume for discussion that you will have time to open the safe while not under fire and have a few seconds to arm yourself. If not, then I would reach for whichever of the loaded handguns could come out first and firing. After getting some space and time, if possible, then I would pull out a longer gun and stuff the handguns in my belt as below.
If I was in a spacious home during daylight hours where lighting is adequate and space allows for shots over 25', not a lot of corners or small rooms, then I might lean toward the AR-15, but I would grab it only after quickly belting the 44 special as a close-range, one-hand backup gun. I would also put the 380 in my belt on the off side if time allowed. Be sure the AR scope is turned down to the lowest magnification setting if a variable.
In a tighter space or at night I would prefer the shotgun loaded with alternating rounds of 2 3/4" 00 buck and slugs. The lighter rounds would reduce the possibility of collateral damage. I would keep a small flashlight strapped to the business end of the barrel that you could turn on at night. Put it far enough back on the barrel that the light illuminates the front sight bead. Then if given time I would tuck in my handguns as above.
While the .223 may well be the best round for rapid energy diffusion in the target, the weapon configuration of the AR-15 (24" barrel and especially the scope) would make it much less manueverable in a close-range situation. If collateral damage is a high concern (such as in a home with tight quarters and many occupants), then I would try to find someone to handload some reduced loads of the slugs (to about 900 fps) for me or do it myself if I'm a handloader. If not I would avoid the shotgun or else go all buckshot with one or two last slug rounds only. The handguns would be loaded with hollow point ammunition.
An alert house dog is an invaluable defense in a home intrusion, especially at night. First, it will wake you and/or warn of an intruder faster than you will generally know yourself. Second, it may deter the intruder, causing him/her to abort the intrusion and avoid a confrontation altogether. Third, it gives the intruder an immediate obstacle to deal with, possibly one that wasn't anticipated. Fourth, the dog may actually handicap the intruder by attacking or take a bullet that would have been aimed at you or a family member. While it is heartbreaking to lose a beloved pet, it is a worthwhile price to pay for your own life and that of your loved ones.
