I don't wear a backpack at the moment, though I think I have a vintage Fjällräven "Kånken" stuffed away somewhere. I'm not eager to get one either, as my experience tells me, that it will be getting very little use. That being said I find myself wanting one of these Klettersacks from Topo Designs. The fact that they are getting good reviews from a lot of reliable sources doesn't make them any less desirable.
Topo Designs seem to have just the right ideals and ideas in order. They started out making everything themselves (Topo wa founded by three friends), but now they make everything in a LEED certified workshop in order to be able to meet the orders from Japan.
They use proper materials such as 1000 denier cordura nylon, leather and mil-spec hardware. I for one love mil-spec, so that is one massive plus in Topo's favour. In addition to this the bags are also very affordable, and their daypacks are even cheaper. Of course if you live in outside of the US, you have to take custom fees into consideration, but it still makes for a good, affordable alternative.
I look forward to seeing where Topo Designs are going. They are definitely a brand to follow. I have read somewhere that they will be producing apparel at some point... Interesting.