There is a new type of rechargeable batteries by Rayovac called "hybrid" (Sanyo also makes a similar one called "eneloop"), and they come fully charged and claim to hold their charge for 9 months when not used. They are made of the same elements as standard NiMH rechargeables, but the nickel-metal alloy is treated with a chemical process that allows the batteries to hold their juice longer. I wonder if these would be okay for the Wii controller?Just so everyone knows, Nintendo's official stance is that you can only use NiMH rechargable batteries and that anything else could kill you controller and void your warrenty.
http://seattletimes.nwsource.com/html/businesstechnology/2003494774_batteries260.html