No doubt, the best batteries I’ve used are Sanyo’s Eneloop cells. They’re NiMH but the self-discharge problem is pretty well licked, and Sanyo are the ones who solved the problem.
Eneloops are still the best, but there are more makers now of LSD (Low Self-Discharge) NiMH cells. Usually marketed as “ready to use”, their initial charge should still be available at time of purchase.
Sanyo has a fairly broad range of chargers available to go with these things, of which I have a couple. But to really get the most from my cells, I use the LaCrosse Technology BC700 Alpha Power charger. A very good combination for me.
— Wayne Ruffner
I use Eneloop NiMH cells in my Canon 580 EX Speedlight strobe and have been perpetually impressed by their rapid cycling, and ability to hold a charge over time. Of the sixteen I originally bought two years ago, every single one is functioning at near full capacity.
— Oliver Hulland
[We originally reviewed the Eneloops in 2007, but I was impressed to see that not only do they remain the standard amongst heavy battery users, but that they have improved performance (lower discharge over time, and 500 additional recharge cycles) and felt that it was worth re-reviewing to reflect that they remain the best rechargeable battery.--OH ]