I'm not a vegetarian for a number of reasons, but am certainly concerned about animal welfare. In addition to the many extinctions and habitat destruction of the modern era due to human action, there's also the ways that industrial food production multiplies cruelties. I found this Christopher Hitchens piece (a book review) thought provoking.
"Political Animals
A new book asks all the right questions about animal rights, even if it doesn't canvass all the possible answers."