Being a big fan of the adult backpack, I have to say there are times, the rarest of moments, when a backpack can come off a wee bit unsophisticated. Thankfully I've recently found this Japanese-made canvas bag ($215) at Portland's Alder & Co. that combines the maturity of a shoulder bag, the simplicity of a ditty bag, and the comfort and ease of a backpack (while still maintaing the understated nonchalance and radical swagger of wearing just one strap of a backpack).