Seriously, twenty bucks and a cell phone, just in case. Go to bikeforum.net and browse a little, do a search or two, and if you still have questions post them there. Those guys have studied the various aspects of bicycling to the ninth degree. Lights depend on the nature of your ride and your budget. I've been looking at the Magicshine P7 lately, inexpensive and the quality of light that I want, but I'm haven't found too much information on its construction quality and durability yet.
