After carrying it for a couple of weeks, I am really liking the Zebralight SC64w. I have 2 quality 18650 Sanyo NCR18650GA batteries. I keep one in the charger at home, and simply swap them once a month, or as needed.

I carry a Zebralight AA torch in my bag, and some extra Energizer Lithium AA's. If my primary runs out, I have a backup that can use inexpensive, widely-available batteries.

An 18650 battery has roughly the capacity of 4 AA's, in a package that's only a little bit bigger.

To me, this beats all: EDC a good quality rechargeable with replaceable cells, and keep a backup AA for emergencies.