[mikester]

If it takes standard size batteries then I would look into Lithiums - if it takes AAs then the 14500s usually fit in place or replace the flashlight with an LED style that can handle the voltage of the lithium or is super bright on an alkaline.

Nimh are worthless in my opinion unless you use them all the time. Left to sit they literally die. NiCds have their own issues which are old news.

I've replaced almost all of my traditional lights with LED lights (lots of CREE) and use alkalines in most but am switching to lithium now.