I think that producing ethanol from prairie grasses would be better than from corn. The only part of corn that is used for ethanol is the kernal. If they would use prairie plants, they could use the whole plant, not just a small part of it like corn. Grasses do not need to be replanted every year like corn does, it grows on its own. There is also no maintenence like corn. All you need to do is mow it and bale it. This would cut down on a lot of the fuel costs associated with corn. The environment would benefit too. The prairie would be habitat for wildlife allowing more animals to live there. Rivers would also be cleaner and flood less often/severely than they do now.
One downside however is less land for crop production which would raise the price of food. But if it would make my gas cheaper, give me more animals to hunt, and cut down on flooding, I could pay a little bit more for my meals.