This is a sample list of things you might take on a week-long trip hiking in a wilderness area. Even more than with other kinds of travel, packing for this kind of trip requires compromises between keeping weight down and making sure you bring everything you'll need, because you have to carry it all with you. Depending on where you're going and the time of year, some of the items may not be useful to you, and there are inevitably additional items you'll want to bring along, but this should give you a general idea of what you'll want to pack.
WEAR
2 synthetic undershirts
2 long-sleeve shirts
2 t-shirts
2 pair of pants (suitable weight for current weather)
2 pair of underwear (long underwear if needed)
2 pair of wool socks
hiking boots
sandals (for wearing when not hiking)
waterproof windbreaker, or at least a jacket.
raingear - ponchos can drape over your pack and save you the expense of a waterproof packcover.
swimsuit?
women: 2 good sports bras
EAT
oatmeal, cereal bars, trail mix, sausage
freeze-dried meals
cooking pots
gas camping stove, matches
plate, cup, utensils
dish cloth, scouring sponge
multi-tool pocket knife (e.g. Swiss Army or Leatherman)
water bottles
plastic bag for trash
water filter or iodine tablets
SLEEP
tent
sleeping bag
foam or air mattress
travel pillow?
GET AROUND
backpack
headlamp or flashlight, spare battery
maps, compass - make sure you can read them before you set out.
hiking staff
STAY SAFE
sunglasses
sun lotion
a hat (to shade your face and/or trap heat)
light trekking towel, bioshower-soap
insect repellent
toothbrush, toothpaste
aspirin/Ibuprofin
anti-diarrhea medicine
survival blanket
blister care (e.g. moleskin, adhesive bandages)
insurance card
ID card
cash, bank card
hankies (dozens of uses, mere ounces of weight)
snakebite kit?
knife
Rope
women: tampons or pads.
