You could throw in the Draco and the new Drake. I'm willing to bet the smaller Drake will just about smoke all of the keychain lights mentioned in this thread. The Draco is even brighter. Both run on rechargable cells, for guilt free lumens.
I bought the Draco in AlTin and can't put the little light down. It is expensive, but it will out perform the others in brightness. Great user interface too, when you get the hang of it.
My next suggestion is the AAA-Arc Miller Mod light. Great light as far as I can tell, but the waiting list is long.