Like I said somewhere buried in my post, I keep some brighter than average LED flashlights in my bags for backup (or if I should get caught out in cloudy/rainy conditions / or wind up riding longer than anticipated)

I use to keep cheap (dollar store) flashlights but had some trouble with them cutting out on rougher pavement.
I like the reliability of the more expensive ones (mine are Husky brand from Home Depot ~$20)

I like the idea of the "hockey Puck" light, though as be seen light.