I use and EDC a Fenix PD32 which is a CR132 x2 light, I clip it in my pocket.
One suggestion I'd make is that IF you plan on using this as a defensive light, not to go too small. Make sure you can use it with whatever handheld flashlight technique you prefer. For instance my PD32 works great for Harries, FBI, neck and cheek index, but sucks for Rogers or Graham techniques (which are actually my preferred holds when I know I'm going to shoot). When taking a class, or shootuing a match, I always go with one of the larger SureFires, they're just easier for me to use when shooting.
Just another thing to consider.
Chuck