One thing to consider for your EDC is the availability of batteries. The nice thing about using a 1xAA light is the ability to find inexpensive AA batteries almost anywhere if you need one. The CR123 batteries, on the other hand, can be hard to find in a pinch or VERY expensive if you can find them.
Of course you can buy CR123 batteries on-line quite inexpensively, but I'm talking about being out in the world and finding that you need a new battery.
Having said that, I still like 1xCR123/RCR123 lights because they can be quite compact while still being bright with good runtime.
While I really like Fenix lights, if I were looking to get an EDC now, I would seriously consider the new LiteFlux LF3XT:
http://www.cpfmarketplace.com/mp/showthread.php?t=186497
Here is an excellent review by CPF member selfbuilt:
http://www.candlepowerforums.com/vb/showthread.php?t=218912
So what to do? My solution has been to carry 2 EDC lights. My primary EDC is a 1xRCR123 based light and my backup EDC is an inexpensive 1xAA light. That way I get the benefits of carrying two lights, and while I use my RCR123 light most, I know I can always find a AA battery if I need one.
If you decide you can only carry one EDC, you might consider going with a 1xAA light than is designed to use a 14500 lithium-ion rechargeable cell as well as regular AA batteries. That way you get the advantages of the the lithium-ion cell, but with the ability to pop in a regular AA battery if needed.
Here are two good choices:
http://www.cpfmarketplace.com/mp/showthread.php?t=181714
https://www.4sevens.com/product_info.php?cPath=93&products_id=502
Good luck on your search for a new EDC.