In reply to crag_hopper_Jay:
I'm a big fan of my Pod Alpine 50. It used to be my "do everything" rucksack. I used it for days out, cragging, scottish winter, alpine, multiday hikes, I took it up Mera Peak, and a friend borrowed it to hike to Annapurna base camp. It has one of those folding closures that allows it to extend hugely (at the cost of being a little unstable when _really_ full), but also cinches down to be quite small.
The biggest issue I had with it was that I was always tempted to put too much in it! So, recently I bought a Mountain hardware scrambler 30 to force me to carry less!