DC, I run a 2AA light for my headlight, and use the white Eneloops for them (2000mah). I always carry a spare pair with me and only replace the batteries when the flashlight gets critically low/dies. This ensures that the batteries are almost fully discharged when they are recharged, which prevents memory effect long term (although this is more an issue with non-Eneloops). NiMH's, unlike Li-Ions, don't fare well when frequently charged small amounts, and this will over time reduce the number of cycles they can go through.

I have a cheap Energizer charger that charges up to 2 sets of batteries, but in pairs only (so 4 total). This isn't the optimal solution, since it can't compensate for slight differences in voltage/capacity, but I always use my batteries in pairs, so the same two always get used together, to minimize any differences between them. I have a USB charger that will charge 2 at once, but since it only delivers 160mA, its really only for emergencies as it would take over a day to charge a pair of Eneloops.

I'm currently working on building a light to take Li-Ions, but those are a whole different animal and the consequences for improper charging/battery matching can be severe.