In reply to Blue Yonder:
I love my Lowe Alpine Alpine Attack pack for cragging/winter climbing duty but its simplicity of design makes it less good for mountain walking / scrambling etc.
I picked up an Osprey Talon 33 last year which is excellent as a do it all pack, though it fails two of your original criteria: simple and hard-wearing.
If I was mainly climbing I'd go with the Lowe Alpine; mainly walking, the Osprey.
As is, I like the features of both for their specific purposes enough to invest in two packs. If I had to buy only one, I'd go with the Osprey.