Anything you train with will help.
Having said that, it's best to have a plan...Arm yourself, retreat and alert the authorities, and not necessarily in that order as time allows.
As far as gear goes...I like my AR for home defense. Look at .223/5.56 ballistics in relation to drywall and such. It works just fine, was designed not to over-penetrate, etc. People will disagree, but...I don't care. :)
The only "tactical" gear I have on my AR is a good sling and a good light, and a good amount of training/practice with the AR along with the sling/light. The sling makes it hard to have your own gun taken away from you when it's tied around you, plus lets you handle the AR a lot more easily, and the light makes identifying---and possibly disorienting---who you're pointed at a lot easier. The only other thing I could see adding to the AR for home-defense would be an illuminated-reticle optic, like an EOTech or similar.
