Bad bad poll. No multiple choice, no other. I couldn't select any of the answers.

Headlight-- only need one, but make it a good one. You can carry a small flashlight for emergency if you like.
Taillight-- again only need one, if it's a good one.
Headlight blinkie, totally unnecessary.

Front fork clearnance blinking lights- essential for the driveway pull outs and idiots who just start turning and only think whoops, when see a light blinking right in their eyes.

Sadly the situation is likely to get worst. The new bright car/truck bluish tint lights are bad because 1. they hurt night vision, so other lights be will less noticable, and 2. they tend to be more floodlights than focused spotlights.