If you want the best generators around, see
http://www.peterwhitecycles.com . All the lights he sells (Lumotecs and BiSi) have overvoltage protection, which means you won't fry bulbs by riding too fast.
http://www.sheldonbrown.com/harris offers the Shimano dynohub by itself.
The bottle generators he sells are quite good (I'm told) and fairly efficient. You still get the typical hum of a generator, and there might be some slippage in the rain. European-designed tires à la Continental have a rib on the side to prevent slippage. I would consider that good for the occasional night out. I never had the Dymotec or B&L, but with older generators, I never wore down a tire from a dynamo before it was worn down because of mileage.
If you plan to cycle a lot, the two hub generators are really where you should go. Unless you want to try your wheelbuilding skills (Sheldon Brown's page is great), you might prefer to order a built wheel. No idea of "practical" settings, however, because I rebuilt my own wheels. So here I go:
- On my commuter, I have a Shimano dynohub with a single Lumotec headlight.
- On my tourer and tandem, I have a Schmidt dynobub with a Lumotec Plus (the one with standlight function) and a secondary Lumotec. All have 3 W bulbs.
On all three bikes, I keep a tiny Planet Bike white "flasher" (acceptable substitute in case of power failure -- never happened --, work and camp light, and "safety flasher" in downtown area), and I use independent Vistalite Super Nebula taillights (2-3 on the bike).
Rating
Both dynohubs are totally silent, wether on or off.
When Off, the Shimano has
a little more drag than the Schmidt, but it still is acceptable, especially for commuting. At ON, I don't mind as much the drag as the fact it "pulses" a bit at 20-30 km/h. Again, not a real factor when riding in stop-and-go traffic, but I wouldn't like it on a deserted road. I'm not sure how to describe it, but the "pulse" happens at high speed and reminds me of riding on rough asphalt.
The Schmidt has NO drag when off (it has some in theory, but nothing significant or even observable). When on, the drag is very minimal: drop your tire pressure by 3-4 psi to get a rough idea. It's also very smooth.
I decided to go with 3 W headlights and battery-operated LED taillights to avoid wiring problems between front and rear end of the bike, running wires all along the bike, wires rusting (especially in Winter), etc. I also travel either with a single bike, a tandem, or any of the above with a trailercycle and/or a child trailer, so you could see the taillight wiring nightmares...
In a nutshell, if you plan on a lot of long night rides, the Schmidt dynohub is really worth it. Add a small LED headlight as a backup and you'll be in the major league.
Regards,