The demand for ethanol is forcing up prices for ice cream (b/c dairy herds are fed corn), and popcorn.
globeandmail.com: Ethanol demand sends corn prices popping
Of course, nobody seemed to care when Mexico complained their tortilla prices went up...
But rising food prices kind of misses the point. We now spend less than half of our disposable income on food than we did 75 years ago. The other day I saw an ad for meat at Safeway and beef was selling for $1.50 a pound. That's simply ridiculously cheap. It takes 10 times the energy and resources to grow a pound of beef than it does to grow a pound of produce, yet I can buy it for less than much of the fresh fruit at the store. Between 50% and 70% of the total cost of a beef cow is feed cost, and since most of the beef in the US is finished with corn, the price of corn will have a definite impact on the price we see at the store.
Needless to say, corn-fed beef isn't as healthy for you as grass-fed beef (higher CLA and Omega-3 fatty acids). Corn-fed beef have much higher of bacteria in their guts - requiring them to be fed antibiotics.
Anyway, considering the health impact of beef in general, and the environmental impact of growing beef (corn is a very petroleum-heavy food b/c of pesticides and fertilizer), I'd be happy if beef costs were higher in the store - something more along the line of the cost of fish ($7-$15 a pound).