lol, where to begin.....you probably want to search the threads a bit, there are about a thousand on keychain lights. At the very least, maybe you could give us an idea about what you are looking for? AAA's or coincell batteries? Brightness or runtime?
+1 for Photon freedom microlight and the EO1- for $30.00 you can have both! Photon has about the same output on high as the EO1, plus all the low you could want, and the ability to use strobe, if that is your cup of tea.
I second the Streamlight Nano. It has a better beam pattern then my Fenix E01 (my reflector maybe whacked. there are some strange artifacts around the outer edge of the beam), but they both are blue-ish purple tint... Yuck. It takes 4 button cells for the Nano vs 1x AAA for the E01.