I've personally "taken a few for the team" and have a little insight on armor choices.
For your "home defense" concept I would go with a vest (not a plate carrier) and some sort of tactical vest/MOLLE rig over that. This set up will allow you to "kit up or down" as your situation needs. Just a bump in the night? Level One- Grab your vest and the gun (set up with a light and a couple spare mags). Bumps (plural) in the night? Level Two- Everything from Level One, plus you slip the assault harness/vest on. Explosions and gunfire in the night? Level Three- First two levels, plus your INCH (I'm Never Coming Home) or BOB (Bug Out Bag) bag/ruck.
If you don't plan on bugging out, I'd still go with this approach. I'd stay away from hanging gear off the body armor directly.
Hanging gear off the body armor MOLLE will cause the fabric to stretch and relocate. Over time your plate could end up protecting your beer belly and not your chest.
A plate carrier, as was mentioned, is just that. What some people don't always get is that the "soft armor" in a vest does more than just resist handgun rounds. It also absorbs/spreads out the "punch" of a rifle round. So if you only have a plate carrier and get shot you might still be taken out of a fight or die from blunt force trauma. Additionally, the soft armor is good for arresting jacketing. When FMJ rounds strike something solid (in my case vehicle armor) the copper jacketing can separate from the lead core. This separated copper has the consistency of twisted, evil razor blades. The soft armor in my vest stopped quite a few of those nasty little bastards.
I'm sold on the use of side plates, but not on the groin protector or those silly samurai shoulder flaps (DAPS). Both seem to reduce your mobility enough to not make them useful to me. I would advocate the use of steel plates over ceramic ones. Ceramic are lighter and less expensive (generally). Steel can take repeated hits without crumbling to dust (generally). Be careful on where and from whom you purchase your plates. There are dates and serial numbers on them (usually). Just like any product, these companies institute recalls from time to time. Ensure the one you're buying is not one of those (another reason to buy from a company and not privately).
Unfortunately, with the increase in demand of body armor, two specific and nefarious things have happened in recent years. First, military personnel having been selling armor and plates privately (the armor was still Government Property). Law enforcement has cracked down on this fraud, but well-meaning (naive/oblivious) buyers are usually caught up in the sting. This can result in them losing their "armor money" and/or jail time. Second, and outright diabolical are that some countries (we won't name names here ....cough ....China ....cough), have copied the ceramic plates to the smallest detail and manufactured identical twins with plaster instead of ceramic. Some people have defended them stating, "These toy plates are for airsoft games." For the sake of being "cool", the plates are designed to be perfect copies and are not marked with "Not for getting shot, it's a stupid and dangerous toy." These toys have been found circulating in the REAL body armor market. Though only in private sales and not from companies (that I've experienced).
In conclusion, I recommend getting a vest (not a plate carrier), wearing it in conjunction with some sort of separate chest rig/assault harness/tactical vest, and to get steel plates if you can afford them.
I agree with the other posts that stated to get the armor fit correctly, buy from known and named companies, and to look at and try on different styles if possible. Good luck with your search and I hope you never have to use it!
Hope this helps!