Rechargeable batteries 100%
For flashlights rechargeable LiPo's are the way to go I think.
Sanyo eneloop are the way to go in AA or AAA batteries rechargeable.
Now there's one charger to rule them all:
+1 I am also a fan of rechargeables and that charger looks killer!
I use energizer AA rechargables on most of the electronics in my house. I also tend to favor Energizer lithiums as back up and for carrying in BOBs, EDC bags, etc.
For CR123s I usually get what I can find best deal on(ashamed to admit)
and I can't remember the brand of 18650s I use, but I have been pleased so far.
I also keep a shit ton of D cell batteries(lithium and/or Duracell/any bargains).
I like to bargain shop for batteries when I can.
Sanyo eneloop are da bomb guys. Come pre charged and keep their charge off charger for a long time. Best, most affordable technology I know of in AA and AAA batteries for storage reasons.
Now if you use something, like a camera or flashlight you use all the time go ahead with the high capacity rechargeables.
MOST NiMH batteries have an even worse rate of self discharge. A loss of 1% of its initial charge per day is not uncommon.
Are these the ones at Costco from time to time? or is there another source that you would recommend?
I've only ever found them online. Seems duracel, everready etc have a monopoly on the local stores. So few folks know about the eneloop ones I doubt they'd move off the shelves without some more education.