I thought the LED Lenser T7 was an impressive flashlight (5.4" long, 175 lumens, under 7oz.), but this little Fenix flashlight really knocks it out of the park.

It clocks in at just 2.5" long, weighs under 1oz., and still manages to put out 170 lumens of light. Consider me impressed. It's also made from knurled, aircraft-grade aluminum, finished with a type-III hard-anodized anti-abrasive coating, and is waterproof to boot (at least while the light is on; the seal is looser when the head is turned to the off position).

$22 on Amazon.