Paul Kirtley has a great article on the basics. I pretty much carry the same for a days bimbling, but in a small shoulder bag. Apart from food, I also carry a whitebox style stove, a small bottle of meths, a collapsable snake hook and a monocular. For anything more than a bimble, I carry a ruck with two nato bottles, swiss army mess kit, laplander saw, bigger FAK, my ti mug which fits in the mess kit and three swiss army kuksas stored inside each other just in case I meet some like minded people and can then offer them a brew. If it looks like rain, I'll add a light goretex jacket and a tarp. Sometimes I'll swap the swiss mess kit for a bush buddy and ti pot if it is dry.
Here's PKs article.... http://paulkirtley.co.uk/2010/essential-wilderness-equipment/
Here's PKs article.... http://paulkirtley.co.uk/2010/essential-wilderness-equipment/