I am person who goes a little over kill on lights.. I love riding at night, the roads are just so much more peaceful here in So Cal at night.. I have 4 lights.. Handlebar Arc HID - Flashing Helmet Light (Princeton Tec Aurora)

Taillights - Seat Post - Red Planet Bike LED 7 - Omni Directional and a White Guardian Adventure Light attahced to my seat pack.. I have found that having a red and white taillight really makes you stand out.. The guardian lights can be found at a few places online but a good place is a company called Botach, they carry police and military tactical gear and have some interesting lighting choices..If you buy the light it comes with the belt clip, you do not have to order it extra.. The other attachments are extra. Here is a link:

http://www.botac.com/novlabguar.html