I submitted my 20-30# answer. This includes everything - including EVERYTHING, DAY 1, the hour I step on the trail - what I wear, trekking poles, everything in my pockets, and the minimum 1/2 liter of water that I carry. If I have to take a bear cannister, ice axe or crampons, then it would be 30-35#. This IS NOT valid for true winter backpacking (now add skiis, poles, skins, extra fuel, a 4-season tent, more clothes, more food, heavier sleeping bag .... and so on). It does not include souviners I collect on the way out - rocks, interesting looking wood, other people's garbage.