Enerloops no question.
You can often pick up packs of 2xAA for $10 on sale, either REI or DELL.
Charge them slowly in a regular NiMH charger, they store for months fully charged.
Quick charging (1-2 hours) does not harm them, but neither does slow charge. The important thing is that each battery is monitored individually for temperature and charge status.
Many slow charger nimh will just continue with a slow charge (trickle charge) on the full batteries until you get fed up and remove them. Far from optimal in the long term, little damage in the short term. Most quick charger will PROBABLY have proper monitoring of the batteries because otherwise you'd risk ruining the batteries pretty quickly, a sure way of getting lots of customers complaints on the chargers. On the flip side, a slow trickle charge without monitoring anything at all is a malpractice you could do lots of times before long time effects come into play. For this reason I'd put more confidence in a quick charger than a slow one.
Stay away from chargers that require that you charge in pairs (2 or 4 batteries at a time, but not 1 or 3). If one cell is more depleted than the other you really, really want that cell to be charged for a longer time than its neighbor. If not you'll never get full capacity from that cell.