Cambebak H.O.S.S. http://www.jensonusa.com/store/product/ ... +Pack.aspx
I like these so much, I bought a second one in case I can't find a new one when my first one wears out. Easily the most comfortable pack I have ever worn.
It's big for most mountain bike rides and the main compartment doesn't have any dividers/organizers but I like to bring a large first aid kit and other bulky supplies with me, just in case, so I don't mind. The front compartment holds all your tools and there's a cell phone/sunglasses pocket on top. The hydration bladder is 3L/100oz.
The thing that makes this back is the D.V.I.S. back system, which CamelBak seems to have abandoned in favour of the less effective (my opinion) N.V.I.S. system. Both systems are basically suspension that keeps the pack off your back. It sounds simple, but it's incredibly effective. The whole pack sits away from your back, distributing the load evenly.The airflow it allows also keeps your shirt dry and your water cool.
The N.V.I.S. system attempts the same thing but it's too thin, I find the pack ends up resting against your pack anyway.
Another perk is that the main compartment is waterproof. Perfect for a dry change of clothes!