LED's are hands down the way to go... a Light Emitting Diode, a simple electrical component that when tweaked for a desired application can blow the pants off of any conventional light... as well as the fact that they are much more resilient and tolerant of impact and abuse. with the conversions, you're still dealing with your original flashlight components - so there's no guarantee that your Mag won't wear out - but i'll put my pants on it that the flashlight will wear out before the LED does! the Navy actually has a Mag rechargeable LED flashlight that we use for night-time maintenance on our helicopters... so bright that even when shining it on the ground it hurts your eyes - and stays that bright for a good 4 hours of use, and then you throw it on the charger and it's fully charged again about an hour later...
anyhow, LED's work. efficiently. i stand by them for everything from (obviously helicopter maintenance) camping, fishing, working on your jeep, or when you lose power... whenever, for whatever.
-Stephen