I saw all 4 Powerbooks at CompUSA today, all lined up next to each other (the 3 AlBooks, and the previous TiBook). This was the first time I had seen any of them, and they all looked so much smaller than I had imagined... probably due to the (relative) lack of vertical height. But I can't see how people think the 17" model is too big, I think it would fit just fine in my backpack, and weigh less than a textbook.
Very nice machines...