I've become a fan of the cygolite brand. Their Hotshot Pro rear blinky is clearly superior to what used to be industry standard (the Planet Bike superflash), and their cygo 400 is now my standard (and only) forward light.
Beyond about 500 lumens, bike lights become a hazard to drivers if they're not adjusted properly to avoid direct lines to eyeballs. They're just blinding. I want to be annoyingly visible, but I don't want to be causing accidents, and I feel like the 400 is about the right compromise for riding at night under city streetlights. If I was riding dark country roads, I'd want something brighter.
I run two rear blinkies, one on the seat post and one one the rear rack, because one or the other is sometimes blocked by panniers or cargo.
These days I also run at least one sidelight. There are some fancy ones that mount under your frame, but I've had good luck with the little ones that wedge into your spokes. My front and rear lights are bright enough that people avoid me, but I've had a few close calls with cars approaching from side. Spoke lights are basically like super-reflectors that go in your wheels, and they make it REALLY obvious that you're a bicycle. I basically treat them as disposable items, and buy a new one ever fall.
