Originally Posted by
frpax
For commuting in the dark:
Lights
Puncture resistant tires
Saddle
For commuting in the light:
Puncture resistant tires
Saddle

+1 (but I have to add a camera)
Originally Posted by
thdave
In this order, these are a few of my favorite things:
Fenders with mudguards
Nokian studs
Marathon Plus tires
nice rear rack, with spring thing
Chain guard
Rear blinky (mounted on rack)
Rear blinky (helmet)
LED headlight
Yeah, but it doesn't sing as well as "Raindrops on roses and whiskers on kittens..."