I have been testing LED flashlights for 2½ years now. I can say that things are changing fast. Driver technology is being used to make LED flashlights brighter and way more efficient than the "old" days. This is basically a box that sits between the batteries and the LED bulb itself, making sure the LED gets the voltage and current it needs for max efficiency (like a transmission in a car).
They are pretty hard to find, but if you want the ultimate battery life, look for an LED flashlight with a driver. We're talking about... like 4-10 times the battery life of a resistor run (no-driver) LED here.
The EverLED is one such product, but the driver is somehow contained inside the bulb, so it can be used to replace normal incandescent bulbs (it's the same form factor as the normal drop in flashlight bulbs). Pretty cool.
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They are pretty hard to find, but if you want the ultimate battery life, look for an LED flashlight with a driver. We're talking about... like 4-10 times the battery life of a resistor run (no-driver) LED here. The EverLED is one such product, but the driver is somehow contained inside the bulb, so it can be used to replace normal incandescent bulbs (it's the same form factor as the normal drop in flashlight bulbs). Pretty cool.