I currently use the Lowepro Fastpack backpack, which has a compartment for my laptop, enough room for my camera body with wide angle lens attached plus two to three more lenses, a tripod attachment on the side,
an attached rainfly, and I can fit a water bottle in the side pocket.
It has everything I need — including two large side pockets for water, an internal padded sleeve for a 3L hydration bladder, plenty of internal and external compartments, and
an attached rainfly.