I read something recently that in very dark conditions blinking lights are harded to judge distance. This winter I plan on running both solid and blink. Formerly, I've always put everything on blink.
Current rear setup:
reflector rear rack, loads of reflective tape
cateye LD 1000 on courier bag solid
cateye LD 1000 on seatpost flash
planet bike superflast on rear stay flash
planet bike 3 led on seatpost solid
generic free linkie on helmet flash
The point isn't just that they see you, but that they differentiate you from cars. ...that they do a "what the heck is that" and exercise some caution as they close and pass.