I'll add my usual warning about battery charging and chargers. Many of the cheaper chargers can easily overcharge and destroy NiCd or NiMH batteries because they don't monitor each cell individually. If the cells are discharged different amounts (and this will happen even if they are all used for the same thing at the same time) it is easy to overcharge one while the others are still below capacity. Worse still, some of the most useless chargers just work on a timer.
I'd recommend something like the Ansmann DigiSpeed 4 or the Technoline BL-700. The latter can also do a discharge/recharge cycle to rejuvenate batteries that have been over-discharged. It also lets you set the charge rate so you don't have to charge quickly unless you're in a hurry. Batteries last longer with a slower charge rate.
Battery Logic UK - Technoline BL-700 intelligent LCD battery charger
Something else to consider are the new hybrid batteries such as Sanyo Eneloop. These are similar to NiMH but with a much longer shelf life. They will hold 85% full charge for a year, whereas most NiMH are down to under 75% in just a few months.