My beloved backpack bit the dust last month and I've been on a quest for a replacement bag ever since. Last week, I found such a bag, and I've travelled extensively with it since and am prepared to pronounce it good.
The bag is a Hideo Wakamatsu Super Hybrid Gear II; a hard-shell pack that appears to contain some kind of Tardis, as I have been able to fill it with my two little gear pouches, a pencil case, my sunglasses, my document sleeve, my laptop, a power adapter, two boxes of business cards, a book, a mini-multidriver, a mini-maglite, and a Moleskine. For all that it's got a solid layer of armor, it still weighs in at less than three pounds; the straps and rear are well-padded, with a chest clip. There's an integrated, Velcro-closing laptop sleeve (already saved my ass at the Dallas Fort Worth TSA checkpoint, when I nearly dropped my laptop on the floor). I'm also quite enamored of the slit pocket that can be opened without opening the main body of the case -- perfect for train tickets, itineraries, etc; there's a second slit-pocket containing a rain-cover.
The $109 bag comes in silver (they appear to have discontinued the navy blue and khaki green models; I bought the last green one in the store). My wife's had a Hideo backpack for five years that looks and wears great; I love their design sense, which marries simplicity and practicality with very spare lines.
I have a nice little semi-rigid Samonsite spinner for overnight use, but when that one wears out, I think I'm going to replace it with the Hideo equivalent; it's even lighter than the Samsonsite, and shares the excellent interior design of the Super Hybrid Gear II.