I use the AA Eneloop blacks for the flash (I've only had to change the batteries once, though I've had the flash a few years... they really do hold their charge!)

I use the AAA Eneloops whites for a head-lamp. I only mention this because this lamp takes 3 AAA batteries, and it isn't immediately obvious that the Eneloop charger only works with PAIRs of batteries. Flashes tend to take 4, so they're fine, but if you have something that needs an odd number of batteries, ensure you have some extras kicking around, so you can leave an odd one uncharged until you have a second odd one to charge it with. I kept the packaging in a drawer, and put the fully charged ones back into the packaging, and leave the uncharged ones sitting free in the drawer... sure beats my previous method, which involved using a multimeter to find the dead ones. The odd batteries, when charged by themselves, appears to show a slight negative voltage when tested... that can't be good.