[BillCA]

In a 12-gauge, I'd go with #1 buckshot indoors. Slightly more pellets per round (.30 vs. .33 cal). This helps increase your ability to make hits. #00 buck will obviously work.

For a 20-gauge, your choices are more limited. I've found some #2 and #3 buckshot - Winchester - and that is what my 20-ga 870. In both, the last round is a slug. The extra recoil lets me know it's time to reload.

I wouldn't place too much faith in the concept that the sound of a pump shotgun will cause an intruder to get religious. It can also serve as a warning that someone is awake and give him time to prepare.

Also, think about your bedroom door (and possibly the doorways of your children). Do all of them allow you to fire from a strong-hand position (i.e. right handed shooters stand to the left of the door frame). If not, how good will you be shooting with your weak hand?

Training and practice are essential to success.