In reply to alexrumsey:
Alex
Great question - you've obviously seen all those 'turtles', staggering from tourist trap to tourist trap with a massive 80 litre haystack on their back, a daysack on the front and usually, a bunch of stuff clipped to the outside. We take photos
We've been living out of bags for the last couple of months or so, in temperatures ranging between freezing and 35C. I think the single biggest influence on how much you're carrying is temperature - are you going in the summer and staying low? Or summer, with some cold weather exposure? Or even winter, but with some temperate stuff around the med?
My single best piece of advice is to pick a sack of about 35-40 litres, that's designed to carry a reasonable load (so don't worry about shaving 500g off the pack weight if it means straps like cheesewire. At 10kg+ loading, a PADDED hip belt is a must). Then choose what you're taking. And don't pack more than 3/4 full - you'll always bring more back with you.
My tips for a sack:
Comfort - proper, padded, straps and hip belt
Inside pocket on top flap
Somewhere on the outside to carry water
Top load only
At least a couple of loops
Forget about hydration bladder set-ups
Martin
Ps also give it a bit of a scuffing before you go - makes you less of a target