I rotate between a few trusty EDC (and a few not-so-EDC'able) lights.
Right now - Fenix P2D Rebel-100, which I also carry on trips with 1xAA and 2xAA tubes (when this light becomes the L1D or L2D version respectively) instead of the 1xCR123A.
But often I rotate with the Ti-PD-S (though never if passing through an airport is involved!). And, sometimes I also carry my first Gen SF L1 (in red LED).
But I'll also sometimes carry instead a Lumapower M3 (which I find I keep most in a 2xAA config., so I can use my rechargeables, occasionally as an 1xCR123A), or the Lumapower M1 (XRE CREE - still no upgrade module out from Lumapower).
Finally, I've been eying one of the new Fenix L0D's with upgraded LEDs, there is a Q4 and a Rebel 80 version floating around, but the dealers are playing games (no offering for the Rebel 100 version, so far, which in fact has sold abroad; or, for the Q4 version--again, no Q5 version, which could make sense technically speaking--is only offered in red--so to unload an excess of red-colored inventory).
I think I can outwait the dealers and eventually get the L0D I want - natural (OK, or silver, but this is unlikely), and Rebel 100 or equivalent (or better!). Once I get it, I'll add it on a key chain but still continue carrying one of the others.