Lights

I've got a set of Knogs on my CX bike, and on my Langster purely because they are small, cheap, and effective enough to be left on each bike and provide light when needed.

I'll slap the Hope Vision One on the bars when intending on going for a ride at night, but for not having to think about it city commuting the Knogs are hard to beat in my view.

Not sure.
All the Knogs I've had have ended up letting water in a shorting/battery leaking.

I'm getting on quite well with the Blackburn Flea's.
They are bright and reliable and a completely sealed unit.
Lifetime guarantee an all so any issues are sorted out with a new unit FOC.