I keep an ACR Firefly Plus strobe/flashlight combination in my signaling/communication module. It was a bit larger than I originally expected (5 oz and 5.3" long - my local outfitter had to special order it and I hadn't really checked the specs carefully enough) although the range (2 miles) is simply awesome.

I also picked up a tiny little Pelican Mini Flasher LED last winter (somewhat because I thought it was "cute", although I felt it might be useful to attach to something that I wouldn't want to loose - the backpacker in front or behind me on the trail at night, my tent when I hike off in the middle of the night to relieve myself, or even a knife or hatchet that I am using and could otherwise misplace in the leaves).

Jim