In Colorado, we have the castle doctrine law- so if there's any kind of home invasion where the perpetraitor has a weapon, you are within your rights to defend yourself and your family as you see fit (taking into account the "disparity of force" rule outlined well by Mr. Ayoob in many of his books). However, I assume that 90% of home invasions will be diffused without any intervention of a weapon. Hell, in college I would always go downstairs to a bump in the night, and find a new (drunken) friend to have an interesting chat with. Most of my home invasions went like this- "Hey man, what's goin' on? Nothin man, having a great night, came from our friends house, etc. Yeah, I know them, yada yada.... So, what the he'll are you doing in my house? Whoa-YOU live here? My bad man, thought I was at MY place and YOU came over". Hehe
But yes, I highly agree on a weapon light. It is tough to maneuver with both hands occupied if you're not a police officer by trade.