I use a medium messenger bag for the most part. Getting a large one from my sister for christmas. I run a pretty small rack bag that holds my rain gear and a few tools. and I strap a small softsided cooler on the rear to tote lunch time to time. I personally always liked having a pretty big messenger bag when I didn't run a rack, now I don't even really need one but old habbits die hard, and not all my bikes have racks either.