Cycling in Melbourne Australia
I ride with two lights on the front, two on the back. This is why http://ajenningsfrankston.blogspot.com/2011/03/two-lights-at-front-...
Given that you can buy reasonably bright LED lights for under $5 in any of those cheapo variety shops there really is no excuse for having no lights. Of course if they're worried about spoiling the nice sleek lines of their fixie by cluttering up the handlebars with useless things like lights and brakes, then we can only hope that when natural selection eventually does its job they don't take anyone else out with them.
Lights will help prevent an "accident" whereas a helmet might reduce the effect of an accident.
Damnit. Defeated by logic once again.