So, after three failed attempts, I think I’ve got the right backpack!
My issue was, I wanted something large enough to be able to carry everything in, but still small enough to be able to get it on board planes as hand-luggage, as well as being light enough to comfortably wear on an everyday basis. Previous trips abroad were made with my company’s laptop bag, but it’s getting old and worn now.
I’ve actually eventually settled on a fairly standard 45L rucksack, from, er, Gelert I think. It’s 51cm tall so just fits in most airline’s hand-luggage restrictions (which tend to be 55/56cm). I’d been toying with something a bit more ‘hippyish’ but the ones I’ve got have been just that bit too small, as well as probably not being strong enough. That said, I’ll take one of them along with me as well (it’s cloth, so it folds down into virtually nothing), to use as a kind of ‘daypack’.
I’m not intending to put a lot in the backpack, obviously …