I would recommend a BASIC survival/first aid kit. Mine fits in a small pouch the size of an eyeglass case, weighs next to nothing, and contains: Swiss army knife, button compass, LED flashlight, Bic lighter, a few xtra strength aspirin, water purification tablets, vaseline impregnated cotton balls, a length of duct tape and a length of paracord, and emergency blanket.
I always try to prepare to spend the night out comfortably, even if I am going on a short day hike. You never know when a twisted knee or ankle, or heck getting off trail and getting lost could lead to disaster.