I'm new here, so forgive me if this has been beat to death here on the forums. I've been wanting a small AAA flashlight to use as an EDC light. Something like the Streamlight MicroStream only brighter.
Read that and then indicate whether you have any specific preferences in terms of beam profile, strobe/no-strobe, tail-standability, etc., etc. "best" is nebulous and "brightest" depends on whether you want flood or throw.
If you really just want tiny and insanely bright there are 10180 lithium-ion options (even smaller than AAA), but the battery won't last more than about 10 minutes on high.
Checkout the 4 sevens preon. If you want smaller the Lumapower edc lm21 is a nice clicky. If you want something a little nicer the peak eiger ultra is sweet.