Two Cases: Marware and Booq (Score 1)

I use two cases for my 15" TiBook - a Marware SportFolio Sleeve and a Booq Boa.XL. I would highly recommend both to anyone looking to get a backpack setup for a 15" PowerBook (and, if you left out the SportFolio, the Boa.XL is perfect for the 17" AlBook...)

In the past, I've used LOTS of bags; Spire makes some wonderful bags, and I used the heck out of an Endo with a previous employer.

I bought a Port bag for my TiBook when I actually cared about the "work appearance"; it's a sharp looking bag, and Port goes to great lengths with their air-suspension system. Heck, when I bought my first PowerBook, I bought the Apple-branded Port case to go with it!

I'd still recommend any of these cases, but most highly recommend Booq's bags.