We use them just about everywhere except 9V, which are in the smoke detectors, and the multi-meter. I recycle them out of the smoke detectors and into the multi-meters (2 of them).
I have had verry good luck with the energizer AA (2450 mAh) and AAA (800 mAh)
a good charger makes a big differeng in battery life. I use a LaCross BC900. The refresh part is cool. It will discharge a cell to .95V, and carge it back up, keeping track of the energy in, and then repeats untill the energy in is within 5% of the last time. I have had it bring back old cells.
LA CROSSE BC-900 Battery Charger w/ LCD DisplayDeluxe Travel..