IanHelgesen

The cheapest option (if you know what you're doing) is to build your own. I just picked up parts to retrofit the old chrome bullet headlight on my Superbe with a high-powered LED and standlight for about $30. I'm not certain whether I really know what I'm doing, but one of the members at our coop is holding workshops to help people with DIY lighting projects.

For off-the-shelf lights, the B&M IQ Cyo seems to be about the best value out there. You could save a few more bucks by looking for the older (and dimmer) IQ Fly, but the price difference didn't seem to be large last time I looked. They aren't exactly cheap (~90 dollars), but neither is anything else in this class (there are some cheaper dynamo lights, but most won't be bright enough to see by, and many use Halogen bulbs instead of LEDs). If you do go for this light, you should be aware that there are a large number of versions. The light comes in either a Sport (bright main beam) or Nearfield/Reflector version (dimmer main beam but more illumination of the area just in front of you). Both of these have further options: the Plus includes a standlight and the Senso will turn on automatically in the dark. I believe it also comes in switched (for dynohub) and non-switched (for bottle dynamo) versions.

I haven't found a ton of information on the Sturmey hub (I actually have one, but still need to build it into a wheel). However, the electronics are made by Sanyo, who also make them for the Shimano dynohubs. The newer Sturmey drum brakes are supposed to be quite effective, and the hub seems to be of good quality.