This is question I do not usually ask myself but if you look into the end of your torch you may be surprised what you see. More and more torches are being made with LED's and not standard filaments but what are LED's and why are they so much better? Being a Physics graduate these are questions I should be able to answer, so I will try!
Light Emitting Diodes or LED's as they are more widely known create light by taking advantage of semiconductor physics. Now you do not need to know much about semiconductors apart from the fact that their conductivity or ability to allow electric current to pass through them can be manipulated to make them very resistant to electric current or conduct electricity like a metal. The LED will be a junction of two different types of semiconductors, one which contains lots of positive charges and one which contains lots of negative charges. We call this a PN (Positive-Negative) junction. Now normally these charges cannot approach each other (as we would expect positive and negative charges to do, attract) but if we apply a voltage across the LED using your AA batteries for example, we can push the positive and negative charges together. When the charges meet they anihalate with each other and the energy is released as light, brilliant!
So why is this better than your standard tungsten filament bulb. Well LED's are lit solely by the movement of Electrons (the negative charges I have discussed) . They have no filament that will burn out, no toxic materials like mercury or radon gas are required in their production and last up to 60 times longer than incandescent bulbs according to howstuffworks.com. LED's also do not suffer as dramatically from energy wastage as heat and so in the energy converting into light sense they are more efficient. However single LED's are not as bright as normal bulbs and so you usually see a cluster of LED's rather than a single one in any application. It is generally expected that LED's will replace incandescent bulbs in the future but alot of work needs to go into making them brighter while keeping them cost effective.
So what does this mean for you and me, the consumers. Well LED's are more economical, they just are. Heat is an incredible waste in a standard bulb and so any improvements we can make there will be worthwhile. For camping the slight loss in brightness from an LED torch will not be a problem and as you can see with a quick search on Amazon a very basic 17 LED Compact Torch retails for just £3.98! If you want to be more economical, perhaps make your batteries last that little bit longer and do your bit for the environment then choose LED. In fact why not be really environmentally friendly and combine the wind-up torch principle and LED lighting and purchase a LED wind-up torch like the Varta LED Dynamo Light - Wind Up Torch .