If you do some looking around you'll find the new 1 WATT LED flashlights.
They last nearly 20 times as long as a regular one on the same batteries and are just about as bright except for maybe xenon.
I'm thinking of taking a 6V (4AA's) Underwater Kinetics flashlight that has one of the 1 Watt LED's, and swapping the head out with a 2 cell Lithium model. Now lithium's have twice the voltage, but burn out twice as fast. Key point here is that a lithiem weights NOTHING. Anywho, lith's are expensive but you can get them cheap over the web.
So taking a 80 hour 6V (4AA) lamp head and moving it over to a 2 cell lithium will give me 40 plus hours of light with virtually no weight. Something I want in my backpack for emergencies.... OH BTW the Underwater kinetics are completely water proof, and Lithium battery's aren't effected by cool & heat and have a shelf life of over 10 years.... i.e. if you want a car emergency lite this is the way to go.
One last thing on a LED, they don't tend to blow when you drop them while they are are like incandescents. All around a good thing.
Spot