FYI EZ,
You might already know this but the lithium hold a voltage and then die, no gradual dissipation. I looked at some and they are spendy! I use alkaline and have the NiMh kind too. There are two kinds of Nimh. the Eneloop type is a new chemistry that can be charged and hold their voltage for a good shelf life, there are several different types out there but they all hold a charge better that the older NiMh chemistry. The older ones can come in some awesome capacities in the 2000 ma to I think 2600ma. Those buggers go forever and the best thing about NiMh is you can recharge them at any point of discharge unlike the Nicads. Nicads are old technology.
Sunny Jim