For those of you looking for something light in the backpack department, here it is - The Lowe Alpine Mountain Marathon 32 litre.
Designed for mountain marathons and adventure races, it is extremely light yet very stable due to the teardrop shape keeping most of the load in your lower back. There is also a large front pocket which is ideal as a rapid fill option for hydration systems (it's also compatible for hydration systems inside the bag as you would expect) or you can just stuff it with energy bars, waterproof shells - basically whatever you like that you want quick and easy access to.
This thing is loaded with pockets too - Massive mesh side pockets, a zippered mesh top lid pocket, Hip belt pockets and harness bottle pockets (see below right).
It's also tough enough to cope with being used as a hillwalking daypack if that's what you're after.
So quite simply a great lightweight pack - In stock in the blue colour seen right and a nice lime green. Come in and try it on for size.