I recently sent out an email query to the a2b3 mailing list about backpacks suitable for laptops. In the interests of not keeping useful information in my inbox, here's a summary of sorts.
The list, in no particular order, with some amount of incomplete information:
Land's End: the pack I have has a label, don't know the name of it in their catalog. It's nice. The Land's End backpack page has more.
North Face: the Yavapai, "carries not only my laptop but a change of clothes when I get to work by bike."
Brooklyn Industries: "really like it. However, when I graduated from a MacBook to a Pro, the notebook was a bit too large, so definitely try inserting the notebook before purchasing."
Patagonia: Lightwire backpack "a great deal" right now at least on sale now
Tom Bihn: "As someone who has carried my laptop in it everywhere for the last 10 years, I highly recommend" the Brain Bag.
Spire USA: "I've been carrying a messenger vert bag from Spire USA for 9 years. Others in my family use the backpacks and love them as much as I love my bag. Their bags have had good attention to detail for people connected to their laptops."
Office Depot / Staples: "For the budget minded I found the laptop backpacks at Office Depot/Staples to be very sufficient"
BBP: "It's innovative, big, and while it's always in backpack mode - it still kinda looks like a messenger bag - which to my way of thinking makes it a 1/2 step more acceptable in the rare more formal meeting."
Timbuk 2: "I am using a Timbuk2 Messenger Bag that I got from Bivouac a few years ago. Great bag, and I think it will outlive ME!"
Timbuk2 again: I have the Timbuk2 Underground. It's incredible spacious - I carry my MBP, DSLR + 2 lenses, several books in the main compartment. And then there are the 2 side pockets that carry numerous other gadgets, GPS, power cord, etc.
Franklin Covey: Victorinox: "This spring I finally found a backpack I am happy with. It is the world's greatest compter backpack. It can easily allow you to travel with two computers and accessories, or with just one computer and all your travel needs for a night or two. It shows no signs of wear after four months, but whenever it does fall apart, it will be the first time I ever happily buy the same model twice in a row. Oh, and did I mention that it costs less than $80?"
Deuter: "I have a Deuter that I bought at Bivouac several years ago. I bought the one that was called something like "mega office" or "giga office". It's less daypack-y and more laptop-and-pens-n-stuff-hold-y than most of what Bivouac sells. It's been great - nice features, has aged well."
LL Bean: "I love my LL Bean backpack. My mom got it for me when I was a senior in college (1993-94). It
lived through that year, law school, marriage, our honeymoon (it was my carry-on), teacher certification classes, two teaching jobs, and it is still happy to ride on my back when I ride my bike. I love that bag"
Brenthaven: "I couldn't be a bigger fan of Brenthaven backpacks. I've had one of their models for probably 8 years and it still looks brand new and is amazingly well laid out. They are a bit spendy but I see no signs that this thing will ever wear out."
Thanks to Tom Brandt, Ron Suarez, Joel Dalton, Susan Harris, Mike Monan, Becki Kain, Bill Merrill, Helene Gidley, Chris Poterala, Matt Souden, Brian Cors, Nathaniel Borenstein, Dunrie Greiling, Andrew Turner, Patti Smith, Sean Convery and others.