At the risk of further injuring this dead horse...

the two things I find very nice about the led flashlight setups, and have convinced me to keep on this route, are:
-simplicty
-reliability

A solid case could be made that the two are related, of course.

my personal experience is that the all-in-one, flashlight-based systems are unbeatable for simplity and reliability. Of course, other people will have different experiences, but I personally have had several (low and high-end) bike-specific lights, and DIY lights, and always eventually had issues with switches, connectors, etc.

Plus those overvolted halogen bulbs look good but burn out pretty quick.... Or such was my experience.

for friends 'n relations asking for a bike light, I send them straigh to the Fenix website for a 2xaa light and Wallyworld for batts and charger. cheap, "bright 'nuff", simple enough my grandma can use it no problem.

cheers