The Mountain Hardwear Direttissima 50 is the most durable pack in our test. It's also one of the heaviest. Our testers really would have liked to keep the durability but trim the fat of extra straps and pockets. Though we aren't fond of climbing in this pack, it is quite comfortable on the approach and could be good for humping a big load to a camp.
For a pack that's almost as durable but a lot simpler and lighter check out our Editors' Choice winner, the Arc'teryx Alpha FL 45.