That's true - you should never charge batteries that aren't intended for it. The protective lining which seals the electrolyte in the cell is typically not strong enough to withstand a charge. They'll definitely vent, and either leak or catch fire. The batteries should include a message on the cell itself to not charge them. At the moment, NiMH cells are probably the best bet if you want rechargeables for the Wii remote. They come in a good range of power densities and the the required AA size. Just remember to use a NiMH charger; NI-CD charges can't properly detect the peak and can overheat the cells potentially causing a fire. Personally, with use from myself and my wife (and a number of friends on the weekends) it takes at least two weeks to kill a set of alkaline batteries. We haven't really timed the NiMH cells, since we charge them when we're not using the unit. I'm looking forward to picking up one of those charging stations, so we can just sit them in the charger without taking the cells out.