I drove past a cyclist this morning who had flashing red LEDs mounted into his bar ends. They were pretty visible, aesthetically pleasing, and having two lights spaced apart seems to convey "vehicle" better than a single tail LED.

Does anyone use these, and if so, do you recommend them over (or in addition to) a tail light? I don't ride at night, but I'm looking for something to improve my dawn/dusk/rain visibility.