Without knowing anything about your bike or situation I would say go with a rack. I have ridden with tubular racks, seatpost mounted racks, big seat bags, handlebar bags, etc. Depending on the application, each one has it's advantages. However, a tubular rack is far better at carrying heavy loads and offers more versatility than any of the other options for most applications. If I only had one bike, it would have a rack on the back.