Here's my two pence on the subject, feel free to take what you will, it is after all, only my way of doing things!
I always use my Berghaus Vulcan, size 2. Over the years i think it really is the best rucksack out there. If your only on a day hike you dont have to fill it up, just pack what you need and pull the compression straps nice and tight! On longer trips i can get everything i need in it and the rucksack is very comfortable even when heavy. So, from the lid down....
Top lid pocket: warm hat and gloves, head torch packed in to a small canoe bag. Bahco Laplander Saw. Hobo fishing line.
Main compartment, from the top: plain flour, milk powder, baking powder, dried fruit, egg powder, dry cured meats, dark chocolate, honey. All in seperate ziplock bags. Amount varys for duration of trip, for day trips the bannock is already made at home for instance. I also carry tea bags. A metal spoon. Then all this together in packed into a canoe bag. Can get quite heavy!
Under the above: sleeping bag, in a bivvi bag. 14cm zebra billy can with the following inside; toilet roll, bar of soap in a soap dish, toothbrush, tooth paste. Orlieb 5ltr water bag. Two tea lights and a lighter. Crook/spoon knife. The zebra can is packed inside a canoe bag.
Under the above: warm and spare clothes. For longer trips i carry; a shirt, walking trousers, socks 2prs, ulfrotte thin wool top. 2prs of underwear. Gortex socks. Helly hanson pile shirt. On day trips i usually just carry the gortex socks.....
Side pouches: nato waterbottle in each pouch. A metal mug. Gortex jacket and trousers in one, tarp in the other. A snack and a tea bag.
So thats about it. Helpful to someone i hope? On my person i carry a knife, fallkniven DC4 and a small steel and a flint striker. Map and compass.