Originally posted by esman7 The Energizer Li-ion's are the best out there. They're expensive, but I get em on sale when I see them.
Just a small correction - the Energizers are lithium, but not lithium-ion. The latter are rechargeable, but the former are not. There are no lithium-ion AA's. The Energizer lithiums do work great, but unless you don't shoot much, they aren't really very cost effective long term since they aren't rechargeable. The"pre-charged" / "hybrid" / "low self-discharge" NiMH's are a better bet for most people. The new NiZn rechargeables are also getting good reviews, although they need their own special charger- you can't use the same one you might already be using with other NiMH's you might have.
BTW, I just had my second experience where using AA's bailed me out last night. I had a set of old standard (non-hybrid) NiMH's that I had long given up for use in my camera, but I took a chance and charged a couple for use in a portable digital recorder to record a concert I played last night, thinking they should still work for that (it's much less sensitive to voltage than my camera). Half though the first set, though, the battery died. So I stole a pair of Eneloops out of my camera bag and was able to continue recording.