When I ride early or after sunset, I go whole hog with lights. I currently run a headlight (either halogen or LED flashing one) and 3 different red LED flashers to the rear (one on helmet, 2 on bike) plus a reflective vest that has flashing LEDs in the strips. I'm going for the "Santa Claus' sleigh" look.

Be aware that a small percentage of drunks seem to be attracted to flashing red lights and may drift into you. I know of more than one police car that's been rear-ended by such a driver while stationary on the shoulder with all the overheads on.