Backpacks at the Office: By Danielle Billet, Men's Fashion guide from about.com:

"I work in a very upscale high rise in Seattle, filled with lawyers and other professional types and it never ceases to surprise how many men wearing nice suits are schlepping backpacks. Unless you are a student or are hiking up a mountain, leave the backpack at home. If you need something for your gym clothes, buy a nice looking gym bag (and there are options that don’t have big logos on them), or if you need something to carry your assorted papers, cell phone, day-planner, etc., get a nice messenger bag."