Two big LED rears so you've got redundancy on flat-battery / soaked innards days. It happens. Run them on steady mode so you look like a vehicle, and then gonzo's hindbrain autopilot will navigate around you without him having to actually think. Thinking is when they screw up.

Reflective on your shoes or pedals. Maybe a FireFlute (http://www.withingtoncycles.co.uk/pr...0&node_id=2546) across your back or strapped to your bag, for body viz.