Nowadays I take a small rucksack with spare clothing, map, a couple of 500ml bottles of water, a PSK that includes a (very) small stove, a mug, a poncho and a GPS. I also have my indoor EDC and a waist-pack with more items (including a compass, large plastic bag, monocular, phone etc).

I've not happy with the rucksack itself. It only has one strap that goes diagonaly, but it has about the right capacity for me (10 or 15L). I've not yet found anything that's small, yet well-supported, yet without unnecessary weight.