For a flashlight I can count on Ive tested several, Ive found some imported taclights that just cant be broken and define the word bright.
For my gas piston carbine I have a small light Ive put together and updated a few times with now the most powerful LED (XPG-R5 LED) that 2/cr123 batteries or one 18650 battery can power, its low setting is brighter than any normal flashlight, its medium setting is as bright as any top end surefire Ive ever seen, and its high setting is just amazing (320 lumens), it has a 320 lumen strobe, and one useless setting SOS.
For a handheld flashlight that takes either 4/cr123 batteries or 2 18650s I have 2, one is 900 lumens, but is an older LED and it gets warm, as well burns through batteries much faster. The newest is a 1250 lumen monster that uses the same 18650 batteries as the 900 lumen light, only it last so much longer, the LED is far more efficient.
I guarantee anyone who goes from darkness to either of these lights shining in their face wont be able to see or see straight for several minutes, or longer. In fact the 1250 lumen light is more than painful when shined at you, even at a long distance, its every bit as bright as some of the best spotlights made, also has the 5 settings programmed into it.
This is the 320 lumen light from across my garage in the dark(no other light source at all), the camera does not do it justice, in fact in person its almost twice as bright, but it gives you an idea of what it can do.
This is at 2 car lengths, again the light is alot brighter in person rather than on camera.
In the dark with no other source of light from a few hundred feet away on a night that has a good myst in the air, in person the entire yard is lit up, the dog house is lit up like daylight, but the camera takes away much of the light.
Ill try to get shots of the 1250 lumen light sometime, it lights up the tree far beyond the doghouse entirely with a solid beam, also lights up a few hundred meters across the field behind the tree if shined beside it.
Neither of these are near as bright as the HID lights on my 4-wheel-drives bumper, but then again they are 3200-3400 lumens each (different purpose, also HIDs need to warm up to full brightness for a few minutes).