i like lithium ion batteries, the removable one in cr123 size that is. Unfortunatly mine's are norminal 3.7 volt, so i can't use them in many applications, because the safety feature on my battery kicks in wenn used in a xenon lamp. Or the applicationss don't take the added voltage. But it works like a charm in my 3 watt luxeon Nuwai Q3. But you could invest in a regulated 3 volt rcr123 lithium ion if you needed too...

I actually like to promote lithium ion battery's, they are powerfull and aren't affected by cold, just like plain lithiums batteries. They are cheaper (in the long term) and beter for the enviorment than disposables. They should make AA and AAA in them, with safety's in them ofcorse.

Personally i use AAA more than AA. Most modern stuff i got are AAA. Camera, mp 3 player, headlight, etc.