The "best" flashlight is the one that is most useful to you AND you carry all the time. My personal fave is the Maglite Solitaire - with a mod. The stock bulb is too wimpy for any meaningful use. However, if you replace it with a Tektite LT-3 LED replacement module, its output rivals that of the original AA maglite. Sure - it's a $23.95 upgrade, but it is worth it considering how much light and battery time you squeeze out of that tiny package. Mine rides in the pocket on the side of my TREO 650 case. It is also a great pocket flashlight.
Tektite LT-3