Agree entirely with Jeep here. The larger the pack the more you bring. I am constantly striving to get my kit smaller and smaller to fit into smaller and smaller rucksacks. I have spent too long lugging too much weight over too many miles. Nowadays I prefer to enjoy the journey and try to travel as light as possible.
I don't subscribe to the idea that you can pack enough kit for a week's camp in a 45 litre pack, and don't like kit hanging and dangling off the outside of it when I'm walking, but feel that 60 litres should be more than enough for a decent amount of kit, including food. As ever, the lighter something is the more money it costs but you normally get what you pay for.
Martin