There's more to having a home defense weapon than HUGE rounds or silly gadgets.
Big, powerful rounds can penetrate walls and kill people in the next room.. hell, in the next house.
Complicated weapons and "gadgets" are more of a hinderance if you're not proficient in thier use. You get ganked while trying to turn on your laser.
Keep it simple and "train, train, train"..
I have a HK .45 USP for my main home defense gun and it's loaded with either low velocity Corbon ammo that is designed not to over penetrate or, even better, Glaser safty slugs. The Glaser stuff is almost in the witchcraft catagory it's so cool. Great stopping power, but unlikely to blow through several walls and kill those it's not intended for.
Believe it or not 12ga bird shot in a home defense situation can be very effective at close range since it doesn't have time to spread. And unlike 00 buck you won't have a **** ton of pellets flying through walls.
So, the best handgun for home defense is a quality weapon that you train with and that you train your family on. For those that arn't mechanically inclined there's nothing wrong with a good revolver like the Ruger SP-101 since it can take 38 +p or .357 rounds. For an automatic there's a ton of choices from XDs to Glocks to Sigs.. the important thing is to train until the weapon becomes an extension.
Also, know your target.. it's sad when you hear of someone shooting a family member that came home late and just forgot thier keys.
Lastly, know the laws of your state.. it's a lot different in CA than say Texas or Florida. But, in the end the old saying "I would rather be judged by 12 than carried by 6" always applies.
Be smart, it's not like in the movies