bag of tricks

I love shoulder bags. I have a Timbuk2 which I adore, and the darn thing is bulletproof. The only down-side is that it looks like, well, a nylon messenger bag (which can be a bit alkward in more formal or professional environments).

Here is Cory's recommendation for a shoulder bag: Czech Plumber's Bag (and a comfy replacement for the shoulder strap). They even have a fancy shiny leather version.

... and mine if you can live with the nylon-look; Timbuk2's Classic Messenger Bag (Large).