By far my Lumintop Tool 2.0 AA. I like it so much, I bought a second one that's sitting in the little tchotchke tray on top of my PC tower, unused, in case something happens to my EDC one so I can put it into service right away.
This light isn't super powerful or fancy, it doesn't run a firmware with a million modes, and it can't cast in a bunch of colors. But it's never, ever failed me and it's got enough high and low range that I basically never use anything else. Much to the disappointment of everything else in my Drawer O' Flashlights, which continue to go unused.