(In case the above link doesn't work, try this: [link])
It's really quite good at this: it has a special pouch for laptops inside, a good amount of padding and a huge amount of space inside. It's also easy to fold down the top if you don't need all of the copious space.
Funny story: I slipped on ice while wearing my Nomad bag, with a laptop inside, and landed flat on my back. Any other bag, and I can probably guarantee things would've broken: the Nomad kept my laptop sufficiently protected that there was no damage. So it definitely seems to work.