I like one cell lights too. I have several CMG Infinity Ultras, an Arc LSL-P, Arc AA, 2 Arc AAA's, TnC Key Lux AA 350, CMG Sonic, a couple Inova X1's, and one that I can't remember the name of- same size as the CMG Infinity Ultra, but has a Luxeon 1 watt and is chrome (is it called the Chromestar or something?) And I'm not sure if it counts but I also have a couple Pal Lights, and another 9-volt 2 led light.
The one cell lights definitely have appeal. I'm considering getting a Surefire one cell light in the future.