Well, let's see... The KL4 is bright and the KL1 runs forever, but you can't have both. It all depends on your needs/wants. Do you need lots of light over a relatively short distance, or just enough to read a map or book? Are you stuck on SF? The only thing I know- noone escapes emptyhanded.
I am looking for a bright flashlight for every day use to carry around. Already own the Dominator 10X but that a little large for the old jacket pocket!
The E2e with KL4 head and the L4 are the same light. I'd suggest going with the L4 with rechargables as was already mentioned. I would hold off on the 2-stage switch until you try the light and really feel that you need it.
The KL1 is not as bright as the KL4, and is a decent thrower. On the other hand the KL4 is a flood with little if any throw. I have put the KL4 on an Aleph body that accepts either 2 x 123's or 1x protected 17670. (Most of the time I EDC my KL4+Aleph setup.) Plus I have an Aleph 2-stage tailcap. Currently I have the KL1 on a Vital Gear 3 cell body, powered by 2x protected 17500 rechargeables. Another thing about my setup with the KL1 and Vital Gear body: I can run the light with easy-to-get alkaline AA's.
Verily I sayeth unto you in typical CPF style: Get both the KL1 and KL4!!