best light to put on my keychain

+1. The nano is the shit. Cheap, functional, easy to use, small. Fuck the rest. Except maybe the DD if you can justify it.

Or get the bead topper, so it's bling, function, and personalized goodness.

I've a Micron Photon, but wouldn't recommend it directly, because it's a press to work light. You just press a button and there is light, if you don't press it anymore no light. But this light is light and IIRC not that expensive and so far pretty durable. If mine goes dead I'll most likely switch to a Fenix E01 or E05. The reason behind this, is that I want to have to function to switch my lights constantly on and put it somewhere so I've my hands free, which is not possible with the Micron.

Hope this helps and sorry for the not as good as I want English. Dunno, sounds a bit weird, might look over it tomorrow to fix it

Nano gets my vote too. Sweet little light, especially for the price!