A .40 S&W Glock is a decent choice. A Glock 22 in .40 is my issue sidearm, and it always seems to work. My wife has an issued 9mm Glock 17. I usually carry a .45 ACP Glock 21 as my EDC, as it is on the "approved" list. Each of these allow the use of a weapon mounted light. I also keep a flashlight or two handy. But, one of my first actions if I'm concerned about intruders is to get the house lights on (and a 911 call)! If you've ever cleared a building in the dark with just a weapon light or flashlight, you soon realize it is NOT an easy task.

I've got a pile of N-Frames in all sorts of calibers, and would feel just fine armed with one of them....IF I couldn't get my rifle or shotgun.