Depends .......
Do you want an AA size light .......
Or a fatter CR123 size light ?
The CR123 battery is shorter but larger diameter.
AA lights are easier to carry in a pocket. (smaller diam.)
And Eneloops are rechargeable , but Primary CR123's are not.
Did you want to consider rechargeable Rcr123a's ?
There's lots o'info here on 123 size batteries ...... if you use the search.
And also look for info in the "Flashlight Electronics - Batteries Included" forum .
That's where we discuss batteries .
.