Corn syrup, however, isn't like some other sugars. It is processed by the LIVER. This means that your body processes the fructose as though it were a TOXIN. Same for agave nectar. There is a host of issues that are directly related to HFCS...and all "sugars" aren't created equally so it's good to take a little time and learn about each one before deciding which one you want to use.
That whole article quoted is interesting and worth reading.
I am glad you brought up Agave, as many believe that it is a healthy alternative, well that is how it has been marketed. It is just as bad as HFCS based on how it breaks down, i found this out after getting an ulcer and switching to Paleo. We stick with raw honey and we have used the organic brown rice syrup for baking. The brown rice syrup gives eveything a nice carmelized nutty flavor. I will have to see if I scanned the bottle for GMO status, I can't remember.