In reply to Thom.milburn:
A lot of people are recommending 35-38l packs.
Are you used to filling 45l? Do you think you will ever want to carry bivi kit in the pack?
I was looking for a pack for similar requirements earlier this year and after a LOT of looking at stuff, and deciding that extra capacity is worth it for the occasional bivi, I went for the Lowe Alpine "Alpine Attack".
If I could have managed with less capacity, I might have gone for the Haglofs Roc 35 which looked very neat and bombproof (the red-and-black colouring lured me too, though). Osprey Mutant 38 was in the running too. There was a lot of unsuitable tat out there.
Funnily enough I gave serious consideration to the North Ridge Ballistic 35 and 45 as Nathan93 recommends (I thought they had all the features you'd want, nothing extraneous, and were light), but I decided against them because I thought the build quality might be a bit questionable (I made a few inspections of these bags in my local Go Outdoors). Nathan says they seem durable though, so might be worth a look. North Ridge is the "house brand" of Go Outdoors, much as Quechua is the "house brand" of Decathlon, so it's probably unlikely that they'd sell tat under that brand, as it would impact on Go Outdoors as a brand if word got around.
I have no regrets about buying my Alpine Attack. It's only had 6 or so mountain days in the Alps, plus a load of cragging in the UK, so I can not comment on durability, but it ticks all the boxes. I got it on a special offer for about £90. If you go for an Osprey Mutant 38 try ratrace.com, they sometimes have them cheap (not right now though, it's £90 - I could have had one for £72 earlier this year)