Don't forget the wheel reflectors! Yes, they look crap in the daylight, but they rock at night - great for side-on visibility. Also, I reckon these and pedal reflectors really say 'cyclist' to the driver's subconscious. Well, they do to me when I'm driving, anyway.
I picked up some black retro-reflective tape from some US website, damned if I can remember the name now though.
I stuck some on the rims before I got the wheel reflectors, and they do a good job. Plus, because it's black you can't tell it's there normally. I also stuck some on the back and sides of my helmet, in a chess-board pattern. My mrs says it's quite eye-catching when driving behind me at night. And again cos it's black it doesn't look crap at other times (and let's face it, we're (almost) all a bit vain about bike gear!). I also wear a road-worker style orange hi-viz vest with loads of 3M retro-reflective stripes, and the helmet has a flashing 1W LED on for getting attention at side roads and roundabouts, when the other 1W flashing LED isn't necessarily pointing towards an oncoming vehicle.
And... that bottle in the cage is the reservoir for an Air-Zound - 115 decibel air horn. It's saved me from a couple of crashes when drivers have pulled out on me despite all the flashing lights and retro-reflectivity. Makes them think something motorised is a hell of a lot closer than they thought, and they slam the brakes on