I use varous batteries, AA come from years of old camera batteries which are still good, and some sub 'c' nicd's from some old remote controled cars ( the rc radios also donate AA's).

The best source of good light and rechargeable batteries are my old battery powered tools, these also make it easy to carry a spare and have 1hr charge capability.

Your use of dry cells is very good and at least lighter than a 5Ah lead acid