minimum I carry water, crackers, multi tool, 4 c02 canisters and dispesnor, extra tube(s),qwikstik tire lever, small first aid kit w/Benadryl in it( Im highly allergic to stinging insects) in case of allergic reaction, cell phone, i.d.,shock pump.
I usually carry more than that like patch kit, allen wrench set, etc. and will be adding some duct tape to my seatpost. great idea, thanks.
I also use a Deuter M3 hydration pack to carry the stuff