I was not looking for a backpack really - more of a soft, rectangular and reasonably smart bag, but many turned out to have straps. The Timbuk2 Wingman, for example, was getting just a little too casual for me.
I like the idea of straps but wonder, practically, how often I would use them. If the bag is to be used for holiday travel, sure, I get that, but for normal business travel I think something with a shoulder strap and handles would be fine.
The more I read about this stuff the more interesting it gets. Perhaps a bag could be had with leave-at-home straps? Or made custom? Now that would be cool