Lights

Although a competent lawyer will fight tooth and nail to avoid this, and it will depend on the circumstances. Pedal reflectors are irrelevant in many common types of crash, e.g. cars pulling out of side turnings, overtaking and then turning left, doorings etc.

On the other hand, as any driver will tell you, coming up behind a cyclist at night you're left in no doubt about what's coming if you see those two amber flashes oscillating 180° out of phase, so if you don't have reflectors it's a good idea to get shoes with retro-reflective features on the ankles or similar.

Got retroflective tape stuck to my winter boots. Probably dosen't score me any style points, but then nor does the flouro jacket, and all the fashion cyclists are back on the train until April at least.