When I am backpacking, I bring the following. On my last hike to the top of Mt. Whitney, backpack was around 55-60 lbs, initially. It got lighter and lighter as I ate my way through it. <img src="/images/graemlins/grin.gif" alt="" />
Clothes
1 poly t-shirt + one that I am wearing
wearing cargo pants
1 pair of liner and hiking socks + 1 of each that I am wearing
underwear
fleece
rain/wind shell
+/- more layers and hat if its cold
bandana
hiking boots

Major stuff:
North Face Backpack
Hiking poles (Black Diamond)
North Face 2 person tent
REI inflatable pad
North Face sleeping bag (for appropriate temp)

Gear
Leatherman Wave
First aid kit, similar to Weekender by Adventure Medical, but supplemented with extra bandaids and drugs
Resque Howler whistle
4AA Underwater Kinetics eLED flashlight
Inova microlight
matches + paper for tinder or notes
Heathseets Emergency blanket
lightstick
Fold flat duct tape (Coghlans)
small sewing kit
50 feet of paracord

Hygene:
2 oz bottle of Purell sanitizer
Fresh Bath wipes
toothbursh/toothpaste, travel size
sunblock
Chapstic
toilet paper

Food and water:
MRE entrees 3-5/day
crackers to use as side dishes
Nectar Cliff Bars http://www.clifbar.com/eat/eat.cfm?location=nectar These are really fresh tasting compared to other once! icon_razz.gif
Hiker water filter by Katadyn
Micropur MP1 water purification tabs
Camelback 3 liter bladder (fits in a pocket inside backpack)
coffe, tea, sugar
mess kit
dry Gatorade/ liquid GU
penut butter and jelly packets

Misc:
Sunglasses
MSR stove
Vectran bear canister, if needed http://www.ursack.com/home.htm
insect repellent
camera
Diamox tablets (if at high altitude)