I've been bike commuting all year 'round in Cleveland for 33 years. My rides take me from downtown out to the suburbs.
The street lighting varies from bright to moderate to none at all.
Most bike accidents with cars take place from the front or side; rarely from the rear.
One good bright blinkie like the Planet Bike works fine from the rear. I've seen folks use multiple rear blinkies but think this is superfluous. I've never had a close call from the rear.
From the front, I generally use 3 types of lights:
One to get driver's attention - a red or white blinkie.
One to light the road well enough to spot a chuckhole, downed tree branch, patch of ice, etc - a bright white steady light.
You can get cheap ones from Dealextreme plus a rubber mounting bracket. So far they've held up rather nicely. The Planet Bike one is just about equally bright.
Both of the above are mounted on a handlebar segment fixed securely just above the front fender, so no handlebar bag, etc can obscure it and it is relatively protected from road spray and salt and as close to the road as I can get it without mounting on the fork (which would then be subject to horrible road spray). They are also mostly blocked from my view by the handlebar bag, thus don't annoy me with their light.
One helmet light to point at drivers either coming a bit too fast from the side, or coming in the opposite direction and looking like they're about to make a left turn across my path. The Princeton Tec EOS bike light with helmet attachment works well.
Over the years I've noticed drivers becoming ever more impatient, frantic and frazzled and thus more of a risk to me. My lighting has improved to take that into account.