I know of two more night-lighting options. One is the Spoke Sparks or Tire Sparks:

http://www.beseenonabike.com/shopuk/popup_image.php?pID=91
http://www.beseenonabike.com/shopuk/...e.php?pID=126\

The other is the Hokey Spokes:

http://www.hokeyspokes.com/

They are a bit flashy but also a bit of fun. I have a pair of the tire sparks, but I got them just before the daylight started to return so haven't really had a good test run with them. They worked really well. They are motion activated and they blink. They're also a great conversation piece while you're waiting at a light.

The hokey spokes really interest me because they're a bit more artsy and you can display messages. Do a search on YouTube to see some video of them in action. They're just about as much as the DLG, because you need at least 3 for it to work, apparently. I'm concerned they might be more of a distraction and less of a safety feature, but I think they would be great for critical mass rides, etc.