Road bikes and dynamo lights

I've got a Roadrat with a shutterprecision hub dynamo, and a Busch and Muller Cyo T senso, and a can't-remember-what rear light.

Brilliant. It's expensive to set up, and a pain to rebuild a front wheel, but the lack of hassle more than compensates. The light is plenty bright enough (I ride on a riverside cycletrack with zero streetlights, and no problem even in winter) and you just leave it turned on all the time. No batteries. It's bolted to the bike with torx screws so pretty much thief proof (esp. as it's useless without the hub and wiring.)

No noticable drain on speed or pedalling power, and the only drawback is you can't switch off the rear light, so you'll constantly have people either telling your lights are on, or kindly fiddling with your bike trying to turn it off. I've had the wires pulled off before by someone trying to switch it off. I've since put a little sticker on it explaining it's a dynamo and will turn itself off in a few minutes.

One annoyance is that it seems to be near impossible to find a rear light that can be attached to a seatpost, they're all for a rear rack. I had to make a little adaptor to fit mine on.