I use Eneloop batteries. They're great as they have very little idle discharge, so you can leave them on the shelf for months and they're still good to go when you need them.
One more for Eneloop.
Just avoid "lite" versions, these are not for intensive use.
Emil Pozar, http://emil-pozar.photoshelter.com/
|Hot Air Balloons Over Bagan by User9320321874|
|Yellow Warbler by LeeS|
from A Big Year - birds
|Waiting for the Parade by tcoker1103|
from - La Vida Loca - (Black and White Street Photography+ A Border)