For a few years the single brightness mode Fenix E01 in Olive was my EDC flashlight, always in my pocket on my EDC key ring along with a metal USB flash drive, an Inka Pen, and a mini-tube with meds. The E01 always served flawlessly, graciously dimming if the battery (ever) needed replacement.. I recently discovered the 2014 E05, and have switched to the E05 for its 3 levels of brightness while still keeping that reliable "twist switch" operation (I enjoy the "press to light" capability to quickly illuminate and even step through the modes). For the E05 I use a 900mAH NiMH AAA cell, and keep an L92 Energizer AAA in the car or backpack as spare.
The E05 (and the E01) also can be used as an area light in hanging from a 1 to 3 person tent's lantern loop, or a hammock or tarp's ridgeline. The cap from a ChapStick Brand balm tube snaps snuggly on the business end, and with a 9" length of thin guy line attached through its keyring, the E05 can easily be suspended. The low level brightness makes a good low level area light in a small tent.
The E05's brightness 3 brightness levels range from a 8 Lumen low (less than the E01's 13 Lumen) to a brighter 25 Lumens, and then even a very bright 85 Lumens (more than enough for finding stuff, more for looking into the dark distance).
The beam color is a more neutral white than the E01, and is optimized more for flood than throw, which is fine for "finding stuff" or illuminating a good distance ahead with good area coverage.

I've bought several of these for myself and family. It's a dependable key chain light that puts out plenty of lumens.

As others have noted, this may be the best ever EDC light, though not the most expensive one. For most purposes, it puts out plenty of light and has good duration, and definitely more comfortable in the pocket than the popular A123 cell powered lights, which are much more bulky. The build quality is also very nice on this one, as is the balanced beam. I'm definitely going to be ordering some more of these, before the supply of 2014 Editions runs out!

This light is not much bigger than the AAA battery that powers it. Itā€™s so small you donā€™t feel it, but so big when you need to use it. Highly recommend.

This is so small. I don't even notice it on my keys. The beam is great, good tint and shape. The lens/reflector is very strong plastic. These make great gifts. Many colors available. Pair with a lithium AAA and you are good to go.