Semi-Veg here - largely for resource efficiency as well, and for some nutritional reasons. I eat poultry and fish but stay far away from meat. (of course i love dairy which makes me a raging hypocrite.)

Interesting veggie for environment argument here: Ethics of Eating Meat

The interesting stats if you dont feel like reading:

"Whereas one-sixth an acre of land can feed a vegetarian for a year, over three acres are required to provide the grain needed to raise a year's worth of meat for the average meat-eater.

"All too often, so the argument goes, those acres consist of clear-cut rain forests. The toll on water resources is equally grim: the meat industry accounts for half of US water consumption—2500 gallons per pound of beef, compared to 25 gallons per pound of wheat. Polluting fossil fuels are another major input into meat production. As for the output, 1.6 million tons of livestock manure pollutes our drinking water. And let's not forget the residues of antibiotics and synthetic hormones that are increasingly showing up in municipal water supplies."