I have an extra Level IIIA body armor w/ plates. I've been toying with the idea of getting a non-military esque carrier and setting it up as a "go to" vest with a few needed items.
Step 1 wake up, get handgun gun and light, wife on 911 w/ cell and her pistol. Listen, no immediate threat, put on handy vest/versipack or belt (she is covering). Step 3, put on electronic ears and I'm ready for full on CQB, get the kids consolidated, wait on police or perps...lord help them at that point.
So, a time graduated response. Light, cell and handgun immediately, then just upgrade gear and position until you are as ready for anything as your planning (and the perp's timetable) will allow.
Sounds silly typing on the internet, but who here has ever read a news story about multiple armed home invaders, tying up residents and doing all sorts of terrorizing before the police show up?
There's nothing silly or "internet commando" IMHO about meeting such a situation with a gun, spare gun, cell, reloads and light (or 2). Body armor...why not, if you have it? I could care less what a lawyer tries to make out of it later, I'm way worse off at home against surprise intruders, outnumbered, than doing room clearing with a team and air support in Iraq. Yet, nobody questions the armor and gear worn by the military when dealing with armed people in houses.
If you don't have armor or a 5.11 type vest...it's kinda spendy but:
http://dsgarms.com/index.cfm/product/1755_139/covert-ops-vest-w-level-ii-body-armor-tan---large.cfm this would be a "Cadillac" option you could also wear around town!