Most of the studies that I've found that focus on the effects of [high-fructose corn syrup] HFCS and sugar focus on the effects of fructose, as opposed to the combined effects of HFCS and sugar. This is actually kind of a problem. It means that people get all up in arms about fructose, and then they hear "high fructose corn syrup", put two and two together, and the next thing we know, we're hearing about how HFCS, and only HFCS, is going to destroy your children, steal your car, and have an affair with your wife. But it's not just HFCS. Remember that fructose is in regular sugar, too, and the amounts aren't so different.
This is the best bit, but seriously, if you have the kind of friends who fret about this sort of thing, read the whole article and then crush them with your superior scientific knowledge.
Then follow up on the scientific crushing with a political crushing, by offering up an explanation of why corn subsidies are still terrible, even if high-fructose corn syrup isn't.
Finally, if you want more, check out this outstanding documentary by my friend Ian Cheney: