Okay, timeout here folks......
There are a number of misconceptions being thrown around here;
Pilot Sofer; did you read that link I gave you? It addresses your questions as well as things like cell impedence (resistance), continous and burst output capabilities, charging including cycling and so on. Did you know you can get a false peak from a NiMH battery if you charge it too fast with a peak detecting charger? That you can actually ruin the thing by charging it too fast? That AA size cells just don't make good rx flight packs except for trainers or small glow models?
AngLeo; you got it backwards on NiCD's and the memory thing. What happens is say you typically only use 50% of the battery capacity before recharging. At some point the battery will go dead when it hits that 50% charge level rather than going all the way down. So it's a case of the battery developing a memory for where it's usually drawn down to, not the charge level/voltage as that stays the same. Incidently, NiMH batteries can have issues which require cycling them a few times much like NiCD's to bring 'em back.
All that said; A123 batteries are the definitive solution for RC model airplanes IMHO. Some folks feel queasy about 'em as you cannot volt check 'em before flight due to the extremely flat discharge curve so it's hard to determine charge level from a loaded volt check. What you do is figure out how many mah's the model uses per flight and charge accordingly. Those batteries will put out a 30C continous discharge and burst to 50C, don't self discharge to any real extent and we're talking months not days or weeks, can be charged in 20 minutes or even faster if you've got a big enough charger as you can't hurt 'em that way, don't require regulators like Li-Ions or Li-Po's and won't blow up like Li-Po's can either.
The 1100 mah A123 in my old Funtana 90 only weighs 3 ounces and will fly the thing all day the way I fly.
JMHO, but you fellers need to dig into the battery question a bit more, especially if you consider going to bigger models which it seems most of us do at some point.