What you want will depend a lot on the weight and length of the DSLR gear and also on what kind of shooting you do.
When I am going light, I have only a small 1.5-pound camera in a padded case. It is on a neck and shoulder strap. Actually, it came with a wide strap, and I substituted a narrow strap that was lighter. All of that rides in position over my right front pants pocket, so I can whip it out in a hurry for wildlife. Wildlife will not wait around for you to fool with a zipper.
When I am going heavy, the camera with lens goes about 6 pounds, so I have it in a long padded case with a strap in similar fashion. Some of these cases are referred to as camera holsters and are intended to be quicker to open.
When I am going extra heavy, the lens alone fills up an entire LowePro AW600 backpack, and the DSLR body just gets stuffed into some cubby hole.
–B.G.–