Camelback Chaos which is as mentioned above is brilliant.
Camelback Rogue (v. old) which is rubbish, no waist strap so it moves around a lot.
Berghaus Vapour (15L), which has some nice features, but must be the least waterproof pack ever, it’s hardly even showerproof. Like all Berghaus rucksacks I’ve had, it has annoying flaws, that make you wonder if they ever tested it outside the design office.