I use a tiered system, where each level builds on the previous level:
Level 0 - Fair Weather Foundation: Shorts or jeans, t-shirt, underwear, socks, firearm, and hiking shoes/boots. About 10 lbs.
Level 1 - Ascent/Summit Bag - down to 30 deg F and 30 kts of wind: Camelback Hawg w/ 100 oz water, iodine pills, lightweight fleece shirt/pants, lightweight wind/water shell tops and pants, lightweight gloves, microweight balaclava, hat, suncreen, sunglasses, whistle, signal mirror, lightweight knife, bic lighter, micro-light, cell phone, antibiotic, band-aids, and 1,000 calories. About 10 lbs (20 lbs total).
Level 2 - Backpack - down to -20 deg F and 70 kts of wind: sleeping bag/bivy system, heavy gloves, water filter/pump, balaclava, winter hat, thick fleece top, thermal pants, thermal socks, spare underwear and socks, gaitors, alcohol stove + 1 weeks' supply of alcohol, headlamp, GPS, spare batteries, pocket sewing kit, cell phone charger, 1 weeks' supply of food (freeze-dried meals), another bic lighter, some additional medical items. About 25 lbs (45 lbs total).
Level 3 - Bug-out bag: tent, three weeks of food, full med kit, change of civilian clothes, cash, credit card, extra ID, hatchet, saw, bowie knife, fire-starting equipment, backup stove (Coleman Peak 1 or Whisperlite), white gas (stove fuel), tarp, horseblanket, thermarest pad, foam pad, pillow, more spare batteries, camera, portable radios + charger, list of phone numbers and key info, laptop and charger, book (edibles in Colorado), 550 cord, nylon webbing, pen/pencil and notebook, etc. About 35 lbs (80 lbs total).
Level 4 - Frontiersman's Trunk: Several key tools useful for building a log cabin, including books, ropes, shovels, axes, pikes, hammers, nails, screws, screwdrivers, hand drills, planes, etc. Upwards of 200 lbs.
Level 0 - Weather-dependent, but I can stay alive for 2 hours, minimum.
Level 1 - I can survive for 24 hours, minimum.
Level 2 - I can survive for 1 week, minimum.
Level 3 - I can survive for 1 month, minimum.
Level 4 - I can survive indefinitely.