Since getting a scooter last year, I've been looking for good backpack for lugging all my stuff around. I did a load of research and was particularly impressed with all of the reviews of the 5.11 Tactical line of Rush backpacks. The bags come in three sizes, the 12, the 24 and the 72, with each size referring to the number of hours in the field the bag is designed for.
I chose the 5.11 Tactical Rush 12 Backpack, and I haven't been disappointed. Of the colour options, I chose black since it looked the least conspicuous and 'tacticool'.
The bag is made from very tough water-resistant 1050D nylon and has a whole bunch of great features. The main compartment is very roomy (18"x11"x6") with ample space for my work laptop, my chromebook, papers and other stuff. There's an "admin pouch" on the front, with zippered sub-compartments, pockets and pen holders. The top of the bag front has a pocket with room for dozens of pens, flashlight, etc. On the very top, near the carrying handle, is a zippered fleece-lined pocket designed for sunglasses.
The pack is also expandable with MOLLE/PALS webbing on the front and sides.