"Regardless of what you think is better, reflectors are passisive and always reflecting. Not the same for your blinkie when it runs out of juice."
Here you go, Mr. Karsten... read up on just how effective reflectors are:
http://www.sheldonbrown.com/reflectors.html
I'll take a blinkie any day, and run about three. If the batteries on one go, I'm still running two. I do run reflectors on my regular night rides, but they're not primary. Some of my blinkies even double as reflectors. And reflectors are not always on; they need a light source hitting them to be "on". In other words, they need something to actually reflect. No external light source, no on. Incorrect placement, no on. Passive, my foot-- in the way doing nothing is passive, maybe.
But again, fixies are so far down the list they're unlikely canidates for any kind of intervention-- unlike, say, baby strollers.