Light with "LEAST" consumption!!!

Hi friends;I am just diploma passed student, but it really hurts me when i saw any bulb or tube glowing unpurposely.Now a days; every where u can c China Made torchs with white LEDs.These are very very bright and also runs much more time with AA batteries (i.e. Pencil cell).Can we design a circuit which will consume less power to give high lumens light from these white LEDs.one more thing friends...... I am very lee time comes here. So if possible, let me have ur opinions at "<admin: please have all the discussions on the forums 😀 >".I really really need ur ideas regarding this topic. but keep in mind the poor one should also able to build it.Thanx in advance.Bye ! Have a nice time!!