afmcorp,
No, you have not experienced ping because, as I explained earlier in this thread, your car has a knock sensor that will detect the very first little ping that you don't even hear and then retard the ignition to prevent the ping. The retarded ignition timing then hurts performance and fuel economy.
As I said, now that fuel prices are higher, the percentage of cost difference between lower grades and premium is less. Running premium, in the long run, costs very little if any, more money than regular.
orvals,
Great and informative post. The only thing I would add is that WEIGHT is the most important single factor in fuel economy. I'm not recommending that you start gutting your interior like a race car to save weight, but if you tend to carry a lot of "stuff" in the car, such as a heavy tool box, golf clubs, etc., or if you tend let things accumulate, remove that weight from the car as an added step to those you wisely mention.
Have a great day,