I already had a Timbuk2 messenger bag. I had treated that bag terribly and it was still standing, so I was all but certain that I would simply get whatever backpack version of that bag existed when I needed a backpack. As it happened, Timbuk2's offering was lacking, and after researching the other brands I knew of, (Brenthaven, Tumi, Dakine, InCase, Briggs & Riley, Samsonite, High Sierra, etc.) I simply could not satisfy the things that weren't up for compromise in a backpack.
I wanted a black backpack, with simple smart design, that was huge, and oh yes… durable. It had to be able to withstand three years of law school.
I'd heard that a Constitutional law book alone could do in a backpack, and I refused to be the person wearing a backpack and dragging a suitcase filled with books through the halls of academia and elsewhere.