Here's my full inventory of gear, taken after my last 3-day 2-night backpacking trip:
Backpack (Osprey Atmos 65)
Tent (Kelty Grand Mesa 2)
Sleeping bag (Marmot Couloir)
Air mattress (Big Agnes Air Core)
Blue foam sleeping pad + square pad for dog
Small inflatable pillow
2 1-liter Nalgene bottles filled with water
Katadyn Hiker Pro water filter
Small, cheap camera tripod
Headlamp + 3 extra AAA batteries
4 extra AA batteries for camera and GPS
Eyeglasses in hard case
Beanie cap
Lightweight fleece mittens
Wallet
Toilet paper
Baby wipes
Pen & pencil
2 empty Ziploc quart-sized freezer bags (for trash storage)
Magazine/reading material
Breakfast: 2 packets of oatmeal or 1 packet of pop-tarts per day
Lunch: Various snacks, granola bars, jerky, tuna pouches, cup-o-noodles, etc.
Dinner: 1 Mountain House dehydrated meal per day
Stuff sack containing personal items:
1 pair of underwear
1 pair of socks
Travel-size anti-perspirant/deodorant
Toothbrush
Small tube toothpaste
2 plastic grocery bags for storing dirty clothes
Stuff sack containing breakfast, lunch, and snack items (mentioned above)
Stuff sack containing cooking items:
Coleman Max backpacking stove
1 fuel canister
Metal mug for heating water
Plastic utensils
Paper bowls
Homemade fire starters (egg carton material full of wax)
Mini Bic lighter
Small jar instant coffee
50' paracord (used for hanging food in tree in bear country, doubles as extra shoelace, etc.)
Small first-aid kit
2 multi-tools (one standard Leatherman and one small Gerber)
2 extra lighters (one mini Bic, one butane wind-proof lighter)
Ziploc bag containing possibly messy items:
Bug spray
Hand sanitizer
Sunblock
Nasal spray
Dental floss
Chapstik
Small bottle with ibuprofen and any other necessary meds, stuffed with paper towel to keep pills from rattling around (also doubles as dry kindling)
Items that may either be packed or worn on person, depending on conditions:
Jacket and/or hooded sweatshirt
Sunglasses
Handgun
Shade hat
When rain is possible:
Rain poncho
Rain cover for backpack
Everything above, with the exception of the last six items, weighed in at 29.5 pounds. I also have a camera and GPS that I clip onto the backpack and didn't calculate them into the weight.