Fantastic (if expensive) carry light - SureFire E1B Backup Ultra Compact Flashlight

An excellent every-day-carry light. Bright enough for self defense or target identification (if concealed carrying), but small enough to not get in the way. A little too small to use as a self defense tool in its own right.
The pocket clip seems to be wearing faster than expected, but the lifetime warranty will cover it should it break.
Very durable - I've dropped it hard at least 10 times with no damage, not even a crack in the lens.
Is very expensive; you may get similar performance from a Fenix for 1/3 the price, but if you need it to always work, no matter what, stick with Surefire.
Pros: Almost indestructable, reliable, lifetime warranty
Cons: Expensive, pocket clip doesn't feel too strong

This review was written in the old system and had content requirements that are different than reviews written today.