I recently read that Germany loosened the law in 2013 and a generator is no longer required. The regulations of beam shape probably still remain, and countries which don't have that requirement are indirect beneficiaries of the regulation. It has resulted in a large quantity of lights being mass produced that cast a really well shaped beam.

@rapattack, there are two common types of generators which are also called dynamos. There is the hub generator, where the power cable comes out of the hub. And there is the sidewall generator, also called a bottle generator because of its shape. The bottle generator is bolted to the frame. The generator hub replaces a regular old hub.

Advantages to hub generators: lower noise, much lower drag and greater reliability. The bottle generator can be knocked out of alignment.

Advantages to bottle generators: lower cost, lighter weight, no drag whatsoever when not in use.

Then again, the drag of a generator hub when not in use is extremely small. In fact, I can't perceive the drag when I do use it. The drag is so small that I run my lights day and night because it doesn't hurt, and maybe it helps me be seen in the day.

Read more on Peter White's site. Even though you probably won't buy from him, it is very informative.

On one of my bikes and two of my wife's bikes, I combined an antique bottle generator with modern LED lights. It's a nice compromise. I got the generators cheap on ebay. They power the lights just fine, and modern LED lights that are intended for generator power cast really well shaped beams.

I don't know about Australian vendors, but I've had some very good luck buying generator lights from xxcycle in France.