@ Templar,
This may not be good form, and I'll accept correction if it isn't, but I have a 120 Lumen light, and practicing with it, I'd say you are correct about splash from bright lights. I get around this by shining the light at about a 40 degree angle from horizontal. If needed, I can put the light on the BG's face in a flick of my wrist. But with the light on the floor, I can see everything and still be able to flash the guy in a fraction of a second.
@ topic
Often times though, people don't realize that flashlights are not to be left on the whole time. A flashlight that is left on is nothing more than a beacon to your position. Another thing, a bigger light just means that you have more weight on your gun, the more weight you have, the less manuverable it is. Light is right, bright is right. The Z series of Surefire lights are light and as bright as you'd ever need, I know they have some newer stuff, but man I love my Z.
Zhur
(not directed at anyone in the second part of the post, just some topical information)