The Streamlight Protac HL-X is a high output flashlight that can be used for carry, home defense, or any low light task. While the lumen output (measure of light output at the bulb) is impressive, the candella (measure of useable light on a target) is more impressive than most of the competition.
The HL-X has a standard click tailcap, along with a large bezel to increase reflection and give better throw (distance penetrated) and spill (width of beam). The pocket clip keeps the flashlight hidden and the 10-tap programming gives you options of using (or not using) the strobe feature.
The best feature may be the rechargeable battery, however. The 18650 batteries are reliable, have a 300-500 cycle (discharge and recharge) lifespan, and can be recharges with a micro USB charger directly to the battery. The HL-X can also run off of standard CR123 batteries as well.
(*warning: only use new CR123 batteries from Streamight and Surefire. Not only are the battery prices subsidised, but they are US made. Foreign lithium ion batteries have been known to leak gasses and catch fore or explode. Do NOT mix new and old batteries, as this can also create these problems.)
With the exception of some added bulk, the Streamlight Protac HL-X is approaching the perfect handheld light.