I run a solid light on my bike and a blinkie is mounted at the back of my helmet... the extra height of the blinkie is really atention grabbing since it is well above the levek of most tail lights.
Some research also indicates the blinking lights are like a magnet to impaired drivers who will unconciously target in on the blinking light...which is a really bad thing.
I run a 1 w or 10 w led up front and also run a small white blinkie that I mount to the head tube so it's flashing doesn't bother me