Absolutely. Lighting is to the Commuter forum what Shimano vs Campy vs SRAM is to the Road forum. Everyone has a different--and strongly held--opinion. Here's mine:

Nearly all my night riding is done on well-lit city streets--generally well-trafficked ones at that.

I found that the inexpensive blinkies are ineffective. They get lost in the constellation of other city lights. Even careful and well meaning drivers have pulled out in front of me when all I had was a CatEye EL-210 blinkie.

When I added a 10W NiteRider TrailRat halogen, it helped tremendously. Still, given the physical size of the light and its brightness/dimness as compared to car headlights, occassionally cars would still misjudge my distance, thinking I was further away than I actually was.

In February I added a DiNotte Ultra 5 high-powered LED light to the others on my bars. THAT changed everything. Running that baby in its "Uzi Burst" strobe mode stops cars dead. I don't know or care what they think I am, but they see me and yield when appropriate. I've had no issues with cars turning in front of me since I got this light.

I've put two of them on my road bike, and run them on constant mode. I get more than adequate light from them and decent respect from drivers.

Others will say nothing less than a HID will do. Riding with HID-equipped cyclists, I think they're too much light for city streets. They're completely overwhelming. Blinding drivers doesn't seem like a very good strategy. This goes double for helmet-mounted HIDs.