For an all purpose light, look no further than the GoBe 500 Spot from Light and Motion.
Compatible with six different light heads, the GoBe system is ready for any adventure. At its most basic it's a flashlight, but it's far from just a handheld torch. The different light heads (all sold separately) let you change the max output, tint of the light, and even go with a underwater dive setup.
With its great range of brightnesses and an included handlebar mount the 500 Spot is dialed for bike use. The 20° beam is optimized to eliminate hot spots and provide great illumination. Its factory sealed for waterproofing to 1200 meters so rain should be no problem. With a run time of up to 54 hours, the 500 Spot is also good for pretty much any outing.
The GoBe 500 Spot Light comes with the GoBe Handle and Blue Spot 500 Light Head, plus a USB Charge Cable, Bar Mount, Lanyard, Head & Body Splash Caps, Grease & O-Ring.
High (500 Lumen) - 1.5 hours
Medium (225 Lumen) - 3.0 hours
Low (70 Lumen) - 12.0 hours
Extended (35 Lumen) - 24.0 hours
SOS (70 Lumen) - 36.0 hours