The really well written post, Helmet Mounted Mirror, on Beginning Bicycle Commuting, prompted me to look at some pictures I took of my helmet setup a while back.
It started out with a little experimentation by adding some reflective strips on my helmet and eventually grew into its current stage.
When I initially started bicycle commuting (in the US), I did not have a very powerful front light on my bike and I used to ride a lot more in St. Louis, MO.
So, I attached a Black Diamond Spot climbers light to my helmet, which became my first helmet-mounted light. It is the one on the left in the picture below, secured to the helmet with a yellow Velcro reflective band. This is my very first climbers' light and I still love this light. It is a great value for the price. It has both a steady and a blinking mode and has a double-power LED bulb and 3 single-power LED bulbs, which can be operated independently one another. This light runs on 3-AAA batteries, which give it a great battery life. It used to adorn the very front of my helmet. But for balancing purposes, now, it has been mounted on the side of the helmet. This light is not heavy at all.
The second and the most powerful helmet-mounted front light I have is the Dinotte 200L-AA-S. This light is the one on the left in the picture below and it is the one on the right in the picture above. In the picture below, the black pouch contains the battery unit for the light. This light runs on 2 AA rechargeable batteries, which give it a really good battery life.
This is not a cheap light but it is so phenomenally bright and increases your visibility by leaps and bounds. It is a great light to be seen and is a very reasonable light to see with, at night. It has a two basic modes (High or Low) and under each you have the choice of steady or three flashing modes. This light is not heavy.
I use the helmet lights to communicate with motorists, especially with those who are merging on to the road I am riding on. Some people like these lights and some don't and I totally understand and respect that. I personally like having them as they give me a sense of security.
The third most important light I have on my helmet is the Planet Bike Superflash (in the back of the helmet in the picture above). It is a nice product and I would recommend it. It is not at all expensive and it is quite bright for its intended purposes.
These are not the only lights on my bicycles. On my commuter, I have other front lights incluing a Light and Motion ARC and rear lights including a Velleman Strobe light.
Another useful item attached to my helmet is my Tiger Eye Rear View Mirror. It is a great product and it is made right here in Texas, in the US of A!!
The heaviest item on my helmet is the Oregon Scientific Helmet Camera, which I bought for $50 or so at Sams Club. It is an okay camera and the greatest assets of this camera are 1) that it is a self-contained unit and 2) it is totally waterproof (not just water resistant). The batteries, memory etc., are all contained right inside the camera. I do not quite care for the smallish buttons atop the camera, which take a while to get used to. But it is a good asset to have handy, while on the road. The one thing I wish this camera had was a still shot capability. I am considering buying a Hero Helmet Camera some point in time, which can do both video and still shots.
Oh, by the way, the helmet camera, I think is a rude-driver deterrant, don't tell the non-cyclists, okay? :)
I do carry a regular digital Camera in my pannier/handlebar bag whether or not I have the helmet camera mounted on the helmet.
On a lighter note, I have gotten several complements on my helmet setup and have also heard some interesting remarks about my helmet setup, one of which was, "That looks like a tactical helmet". I simply took that as a good joke :)