My newest flashlight is an EagleTac G25C2, and I like it a lot, but it's too much flashlight (and too much cost) for most peoples' needs. I really like the 4Sevens Quark AA^2 and 123^2 flashlights for that -- amazing runtime and fantastic output with rock-solid reliability in one package.

I have no affiliation with any flashlight manufacturer other than owning what some might refer to as "too many" flashlights.