This happened to me.
Mid day, mid week I was at home playing Blackops or similar on my Xbox360. I was sitting on the couch, the front door to this place was on my left. Approximately 50ft from me, but visible if I turned and looked with my head only. I had a screen door on with the handle locked. So I'm blasting away and hear the door yanked open, I turn and I see a guy walking doff his shoes then proceed to walk down the hall. I blink for half a second, stand up into a run. Crank my arm back into a chambered baseball pitch with the intent to throw my controller like a fast pitch into his face. Simultaneously I yell "WTF, GTFO". The guy looks at me from 15ft away and says "oh she wasn't playing games when I left." He then proceeds outside with his small handbag and leaves. I stand there and process the event for a minute then go outside to look for him. He is no where to be found so I go to several different neighbors to say some dirt ball just walked into my place. About 3 doors down a new tenant says she was having a plumber over.
In retrospect at that time (2011) I lived in a townhouse complex, an upstairs unit and my screen door lock wasn't very secure. Though gain access to my front door you have to open my front gate that was waist high.
If he was a threat my plan was to beat his ass with my Xbox controller. If I threw or lost the controller, I kept several 28-34" thick rattan sticks and a 1"diameter pipe next to that front door. Without self glorifying I have a lot of experience training to hit things with sticks and anything handy. This includes people, heavy bags, dummies, tires and the like. If I had to retreat the kitchen was 8-10ft next to the door in which I could have grabbed the next useful weapon. At that and this time I do not have a firearm readied for an intruder(s). I do have a young child, including his mother who are not ready to have one around. I do have numerous weapons placed throughout the house that would seriously dissuade them from continuing to stay on my property. I use a large safe and have thought of the Barska with manual metric access for quick availability, but don't have a high threat level so there is minimal need vs want.