As I have said I really need a pack that has the capability of comfort, durability, quality and reliability.
Frogo,
Most packs from the major manufactures ( I'd exclude Karrimor as they are going through a bit of a rough patch) will be pretty well made and capable of giving good service.
Comfort is a subjective thing what fits me and I find comfortable might be different for you ergo what fits person x on a forum might not best suit person y you'll need to try on what you intend to buy with some weight in it before commiting. I would think I think that is especially true if you are thinking of buying a fixed back pack.
Durability well it depends on what you are doing with the pack. If it's just 'normal' backpacking type stuff most things last a long time if looked after. Ive got a Lowe Alpine backpacking sac that is nothing spectacular has seen a lot of use from me and been borrowed and abused as a loan out / hire pack and it's still going strong it must be 15 years old. If you are going to be hauling it up granite slabs in the Alps or cliping it to the side of a Landrover Wolf then you may want something that is a bit tougher.
Your choices are endless if you're happy to have regular pack colours such as blue, red etc there are heaps of packs out there that are perfectly serviceable for all sorts of activities including bushcraft. If you want something in a subdued OG, Tan type colour then your choices reduce.
Folk on this thread have mentioned a lot of the Classic 'Bushcraft' packs.
Berghaus Vulcan, Karrimor / PRI Sabres, Lowe Alpine etc.
All of these are really good I've got a Vulcan I use a lot and I find it very comfortable and not overly complicated.
I fully expect the waterproofing on the fabric to delaminate as that has happended to my old Roc and Munro. The back gets a bit sweaty and the lid pocket zip could do with being on the other side. Nothing in life is perfect...
However if you're dismissing equally good packs from manufacturers such as say Osprey, Macpac, Arcteryx, Crux, Norrona etc then I think you are doing yourself a disservice.
I'd avoid SAS/Para Bergens, GS bergens, and Alice packs. All are an uncomfortable nightmare...
HTH
John