I have Maha Immedions, low discharge NiMH - I think they are the same as the Eneloops. I get them from the same folks that have the C-9000 charger. I've been using them for at least 5 years now. The lower internal resistance is useful and they hold charge for what seems like forever. By now I have lost track of just how many I have, but certainly there are four in each of my six flash units, some AAAs are in my remotes, head lamp, and some other stuff, and they've now crept into all of my wireless keyboards, track pads, mice and the like. I probably have close to 50 of them now.
The new ones are 2400mah and should yield around 240 frames per set if you shoot at full power, maybe a bit more on an SB-800.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!