I don't know how it would feel to have the weight on one side instead of evenly distributed across my back. I prefer to use a backpack, I got the Traverse Pack from REI and it has a "channel" down the center of the pack that allows airflow. I have a friend that uses panniers but I've ridden with those and the bike always felt back-end heavy.
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"