A panel on genetically modified organisms was held recently, and the lead has also written about it. 

Common points that concern advocates against GMOs were addressed:

Superweeds -  Superweeds happen whenever herbicides are overused. Always have, always will. GMOs are not the problem.

It's just Big Ag - "Currently there are 30 commercialized GE crops cultivated worldwide. By 2015 there will be more than 120. Half will come from national technology providers in Asia and Latin America and are designed for domestic markets. The reduced dominance of U.S. seed companies may alleviate concerns of consumers who oppose genetic engineering because they see it only as a tool of large U.S. corporations."

What about beer? What about insulin? - activists against GM crops tend to focus on battles they hope to scare people about so they leave out the many GM crops that no one complains about. California's Prop 37 specifically exempted alcohol because they knew beer was genetically modified - but they knew people were not going to outlaw beer, so they excluded it from warning labels.

And more resources:

Resource: A Panel of Scientists and Experts Assess the Subject of Genetically Engineered Crops , By K. McDonald, Big Picture Agriculture.

Forum: The Truth About GMOs - Boston Review

Buddhist Economics and A GMO rethink By Pamela Ronald Scientific American Blogs