Night Riding With Heavy Traffic I live in a fairly urban setting and there are plenty of cars around when it gets past dark. The main point of having a bicycle light/backlight (I contend) is not for you to see, its for others to see you. Besides just using lights, there are plenty of other reflective Doohickeys that purport to make you visible at night. (see this thread for an example)

In practice this works just fine in relatively suburban or lightly trafficked areas. Where an extra light on the road does stand out and people notice a bike rider. However, I live in a fairly urban area, and down-town is saturated with light that a dincky bike light will not stand out in the crowd. 

I've experienced this both from the POV of a driver and of a cyclist. Just today I was driving downtown and almost hit a biker with the notorious right hook. Luckily we didn't make any contact, but afterwards I recognized why I didn't notice him even though he was wearing a reflective vest and had a decently bright light. His light made him blend in more with the backdrop of downtown. The oversaturated lighting of downtown desensitized me to certain visual cues that usually would tip me off to the presence of a biker or a car (i.e. their glaring lights in my mirrors). If I was driving down a darkish residential street I would have noticed him right away. 

So what are some good tips on biking at night in urbanized areas, where there are more than just a few cars out after dusk. More specifically, what can you do (that you normally wouldn't do during the day) and besides making yourself brighter that would make your night ride safer?
When winter arrives and brings shorter days, I add additional lights.  As you say, this is just more urban lights, but a bike light--especially if it is blinking--does make you more visible.  I prefer a light with an erratic blink pattern, such as Planet Bike's BLAZE with superflash mode (http://ecom1.planetbike.com/3047.html).  This erratic pattern forces you to the forefront of attention.

Lights and reflectors are essential but are not the whole answer.  I ride at night to be right where the motorists can see me.  It is always important to do this, but more so at night.  When there is no bike lane and no wide shoulder, I take the MIDDLE of the lane.  This is particularly important in an urban setting like Oakland or Sacramento, CA--where I ride.  Traffic in the city is heavy and often not much faster than I am.  Often cars are maxxing out at 25mph whereas I'm riding at around 15-18mph.  I can ride in the middle of the lane and if they're anxious, they can pass me.  The downside of this is that I hear a few drivers sounding their horns in protest.  The upside is that no one is surprised by me.  

No driver wants to damage their $20,000+ automobile by hitting a cyclist.  I'm a big guy, too--I'd damage their car.  So I ride right where they see me.  

Most places where I ride are urban city streets--usually with two lanes in each direction, sometimes a left-turn lane.  I use all of these just as a motorist would--and California state law supports me in doing this.  My goal and the goal of the law here are to be visible and predictable.  I ride like I belong there--without trying to be a jerk about it.  The motorists have a passing lane to get around me--and if they don't, I let them pass whenever it's safe and with easily-recognizable hand signals.  If they're right behind you, after all, you have their attention.  

Be both visible AND predictable.  

Have good situational awareness--know what's going on all around--and react to motorists who may not be doing the same.  

Have a safe ride!