I'll second all the suggestions for helmet, down lighting and side lighting. I look like a traveling carnival, but no one should ever be able to say they don't see me....from the front, behind or the side. I have a helmet light (Stella 200) a small flasher on my handlebars (Flea) Two rear red blinkers (Flea on my messenger bag, Dinotte on my bike), A blue bar LED on my downtube and a green flasher on my valve stem (cheapo from Toys R' Us, with overpowered silver calculator batteries put in it) Not to mention various reflective bits here there and everywhere. Most of this comes off pretty easily for daytime training rides - just the downtube light is zip tied on pretty permanently.