The Good Pocket One Every Day Carry, Est. 2011
Klarus Klarus 2 Klarus ST10 XP-G R5 AA LED Flashlight

This light is very small, extremely powerful (an incredible 140 Lumen) and does is all with a single standard AAA Battery that is easy to get anywhere. It is also water proof and comes with a nifty set of extra features: 4 output levels, SOS, Strobe and Beacon modes.