Why would you want to "clear" your house? Investigating a strange noise (as Frank suggested, by sitting and listening) is one thing, but IMO running towards an obvious threat would be a silly thing to do.
Listen, I live in the country. Any invasion in my area is extremely rare, though it did happen not too long ago not too far away from my house.
I have no intention of "running towards an obvious threat". But I also have no intention of hiding in the corner of my bedroom for every type of noise that I may want to investigate.
Should I hide and call 911 for every little noise? No. I don't know what the noise is, therefore I want to see what the noise is, but calling 911 and hiding in my bedroom is somewhat extreme. It may be something as stupid as my hot water heater making an odd sound, but I don't feel I should hide in my bedroom waiting for something to manifest itself.
I'd find it extremely hard to go back to sleep until I found out where the noise came from, and a quick check would solve that. I believe just about anybody reacts in the same manner, armed or not.
Now, if I heard what I believed was obviously an intruder, I would not engage and would do just what you guys said.