I actually do not think panniers are all that wonderful. I mean they are great for hauling large loads. However, in windy areas they cause an issue with wind drag and I do not like how my bike handles with them on. Rack trunks are much nicer. More aero and all that. Plus, I haul less with a smaller cargo capacity.
Lately I have been riding my road bike with a backpack. That really is not that bad of a thing. Though I can not wait to change it for a messenger bag.
My latest greatest thing since sliced bread happened when I switched to skinny tires. Consequently, I discovered that the reality of riding with skinny tires is directly opposite than the majority of the opinions posted in this forum.