Wheelmonkey, Most everything is personal taste and needs, but two items are paramount. Condition of the bicycle and first aid. The bike and all attached items should be examined before the ride for loose screws and bolts, wheel trueness, tire pressure and lubrication. I carry enough tools and supplies for minor repairs, primarily flat repair. First aid supplies to deal with road rash and aches/pains in the least. A charged cell phone to summon help may very well be the most important item of all.

Brad