I bought a Booq Boa Flow M a few months ago and love it. It is great for carrying lots of digital gear (I use it for my MacBook, iPad, camera, headphones and all the associated cables/cords), though less than ideal if you need to carry lots of paper/files.

The backpack is very comfortable and well-made. It isn't quite as conservative (or expensive) as the Tumi packs, but that was a plus to me.

Check them out at booqbags.com