Great conversation!
I often kick around the cost vs. real benefit issue. A really bright light that is impact resistant is really important. How much is too much for price and how little light is too little?
I'm not sure I want to rely on the brightness of my light to be the stopping factor for someone straight out of county. If I'm in my home, many parking lots, buildings etc, there is some ambient light that can be enhanced by a flashlight. If I'm in my home, I can pretty quickly figure out, even in low light, if there is someone there that is not supposed to be there. Do I need to cover them with a flood light to figure out if they are a threat? Nope, the mere presence is enough. Even a small maglite can serve that purpose.
Yes, there are people who need those high-end lights to do life saving work. And I hope they have one when they come to save me! The low end surefires are a good cross between cost and function and the maglites still hold up pretty well.
Practice with what you have in scenarios that you might face and see how your light holds up.