This Think Tank Retrospective 10, has become my personal favorite walk around shoulder bag. This bag doesn't look like a camera bag, so your less of a target with all that expensive camera gear. Plus it holds just the right amount of gear for a day of shooting.
The Retrospective series of bags are made from tough durable materials that are tough, yet, surprisingly soft and flexible. Even the strap is great - it’s made completely of canvas, it's the perfect width, which makes it comfortable and easy on your shoulder even after long hours of shooting. The strap has a big breathable, cushioned pad that's really, really comfortable. And the shoulder pad features a non-slip grip, so the bag stays exactly where you put it on your shoulder.
The Think Tank Retrospective series is available in various sizes and colors.