I've seen a lot of people in this thread insist on flashing for "safety." But I haven't seen anything here explaining why, how, and based on what evidence is it safer. So I'm not convinced using a flashing light has any benefit. And, having tried it, I found the reflection that comes back at me made it harder to stay in control of the bike (constantly changing level of illumination means that my eyes were never properly adjusted.) If this is the effect it has on me, I imagine it's similar or worse for oncoming traffic.

So, while I have no thoughts about rear lights, and use blinkies myself as this is the standard way of identifying a bike from the rear, I will only use solid lights up front.