Out of all the camera bags I have either used or considered, none were comfortable and functional together. To hope for a the one bag you find to be stylish as well would be flat out impossible. Most companies try and sell a camera bag as a box with shoulder straps on it. Camera bags are designed by camera people, when what you really need is one designed by backpack people. Solution: Put together your own camera bag.
Pick your pack according to your lifestyle. My daily routine includes a bike commute in an urban environment, usually some walking and being prepared for rain. I have to carry around a bike lock and cable, bike lights, some spare tools, a rain jacket and fender just in case. All that in addition to any photo equipment I might need for the day requires a specific kind of bag.
I chose a cycling backpack that has a quick access zipper on the side; the TLevel Inifinity Rolltop 43L. It has adjustable hip and chest straps as well as load lifters, which I can't do without. It has multiple compressor straps to minimize the bag size and there is a back pad frame to put some space between your back and the bag which minimizes sweat. TLevel's come in a bunch of awesome colours and has reflective strips on them for riding at night.
As far as a camera bag goes, it doesn't cut it. So you'll need a camera insert. The Crumpler Large Haven portable padded protector is what I use to store my camera and lenses inside. There are a bunch of brands that make inserts. Crumpler happens to be camera bag brand that made a colour scheme close to what my backpack was. The Large Haven is enough to fit a Nikon D800 with a 24-70mm zoom and a flash with some room to spare. It also has pockets along the front for batteries, cards, and film. The TLevel can actually hold two of these bags easy — though I've only needed one.
There are different means to an end, but the way to choose a bag and insert is the same for everyone; Start with a bag that functions in the way you most like and the insert that works for your equipment. A made to order camera bag beats any out there on the shelf.